Details

Summary

The static error.html template for errors contains placeholders that are replaced without escaping the content first.

Details

From https://kit.svelte.dev/docs/errors:

error.html is the page that is rendered when everything else fails. It can contain the following placeholders:
%sveltekit.status% — the HTTP status
%sveltekit.error.message% — the error message

This leads to possible injection if an app explicitly creates an error with a message that contains user controlled content that ends up being something like this inside a server handle function:

error(500, '<script>alert("boom")</script>');

Uncaught errors cannot be exploited like this, as they always render the message "Internal error".

Escaping the message string in the function that creates the html output can be done to improve safety for applications that are using custom errors on the server.

PoC

None provided

Impact

Only applications where user provided input is used in the Error message will be vulnerable, so the vast majority of applications will not be vulnerable

Severity

• CVSS Score: 1.3 / 10 (Low)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

References

• https://github.com/sveltejs/kit/security/advisories/GHSA-mh2x-fcqh-fmqv
• https://github.com/sveltejs/kit/pull/13050
• https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.8.3
• https://nvd.nist.gov/vuln/detail/CVE-2024-53262
• https://github.com/sveltejs/kit/commit/134e36343ef57ed7e6e2b3bb9e7f05ad37865794
• https://kit.svelte.dev/docs/errors
• https://github.com/advisories/GHSA-mh2x-fcqh-fmqv

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

Summary

"Unsanitized input from the request URL flows into end, where it is used to render an HTML page returned to the user. This may result in a Cross-Site Scripting attack (XSS)."

Details

Source of potentially tainted data is in packages/kit/src/exports/vite/dev/index.js, line 437. This potentially tainted data is passed through a number of steps (which I could detail if you'd like) all the way down to line 91 in packages/kit/src/exports/vite/utils.js, which performs an operation that Snyk believes an attacker shouldn't be allowed to manipulate.

Another source of potentially tainted data (according to Snyk) comes from ‎packages/kit/src/exports/vite/utils.js, line 30, col 30 (i.e., the url property of req). This potentially tainted data is passed through a number of steps (which I could detail if you'd like) all the way down line 91 in packages/kit/src/exports/vite/utils.js, which performs an operation that Snyk believes an attacker shouldn't be allowed to manipulate.

PoC

Not provided

Impact

Little to none. The Vite development is not exposed to the network by default. And even if someone were able to trick a developer into executing an XSS against themselves, a development database should not have any sensitive data.

Severity

• CVSS Score: 0.0 / 10 (Low)
• Vector String: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:N

References

• https://github.com/sveltejs/kit/security/advisories/GHSA-rjjv-87mx-6x3h
• https://github.com/sveltejs/kit/pull/13039
• https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.8.3
• https://nvd.nist.gov/vuln/detail/CVE-2024-53261
• https://github.com/sveltejs/kit/commit/d338d4635a7fd947ba5112df6ee632c4a0979438
• https://github.com/advisories/GHSA-rjjv-87mx-6x3h

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

Under certain circumstances, requests could bypass the BODY_SIZE_LIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers of the application stack, so limits enforced in the WAF, gateway, or at the platform level are unaffected.

Severity

• CVSS Score: 8.2 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

• https://github.com/sveltejs/kit/security/advisories/GHSA-2crg-3p73-43xp
• https://github.com/sveltejs/kit/commit/3202ed6c98f9e8d86bf0c4c7ad0f2e273e5e3b95
• https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.57.1
• https://nvd.nist.gov/vuln/detail/CVE-2026-40073
• https://github.com/sveltejs/kit/releases/tag/@​sveltejs/kit@2.57.1
• https://github.com/advisories/GHSA-2crg-3p73-43xp

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This could result in DoS on some platforms, especially if the location passed to redirect contains unsanitized user input.

Severity

• CVSS Score: 6.3 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

References

• https://github.com/sveltejs/kit/security/advisories/GHSA-3f6h-2hrp-w5wx
• https://github.com/sveltejs/kit/commit/10d7b44425c3d9da642eecce373d0c6ef83b4fcd
• https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.57.1
• https://nvd.nist.gov/vuln/detail/CVE-2026-40074
• https://github.com/sveltejs/kit/releases/tag/@​sveltejs/kit@2.57.1
• https://github.com/advisories/GHSA-3f6h-2hrp-w5wx

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

v2.57.1

Compare Source

Patch Changes

• fix: better validation for redirect inputs (10d7b44)

• fix: enforce BODY_SIZE_LIMIT on chunked requests (3202ed6)

• fix: use default values as fallbacks (#​15680)

• fix: relax form typings for union types (#​15687)

v2.57.0

Compare Source

Minor Changes

• feat: return boolean from submit to indicate submission validity for enhanced form remote functions (#​15530)

Patch Changes

• fix: use array type for select fields that accept multiple values (#​15591)

• fix: silently 404 Chrome DevTools workspaces request in dev and preview (#​15656)

• fix: config.kit.csp.directives['trusted-types'] requires 'svelte-trusted-html' (and 'sveltekit-trusted-url' when a service worker is automatically registered) if it is configured (#​15323)

• fix: avoid inlineDynamicImports ignored with codeSplitting warning when using Vite 8 (#​15647)

• fix: reimplement treeshaking non-dynamic prerendered remote functions (#​15447)

v2.56.1

Compare Source

Patch Changes

• chore: update JSDoc (#​15640)

v2.56.0

Compare Source

Minor Changes

• breaking: rework client-driven refreshes (#​15562)

• breaking: stabilize remote function caching by sorting object keys (#​15570)

• breaking: add run() method to queries, disallow awaiting queries outside render (#​15533)

• feat: support TypeScript 6.0 (#​15595)

• breaking: isolate command-triggered query refresh failures per-query (#​15562)

• feat: use hydratable for remote function transport (#​15533)

• feat: allow form fields to specify a default value (field.as(type, value)) (#​15577)

Patch Changes

• fix: don't request new data when .refresh is called on a query with no cache entry (#​15533)

• fix: allow using multiple remote functions within one async derived (#​15561)

• fix: avoid false-positive overridden Vite base setting warning when setting a paths.base in svelte.config.js (#​15623)

• fix: manage queries in their own $effect.root (#​15533)

• fix: avoid inlineDynamicImports deprecation warning when building the service worker with Vite 8 (#​15550)

• fix: correctly escape backticks when precomputing CSS (#​15593)

• fix: discard obsolete forks before finishing navigation (#​15634)

• chore: tighten up override implementation (#​15562)

• fix: ensure the default Svelte 5 error.svelte file uses runes mode (#​15609)

• fix: deduplicate same-cache-key batch calls during SSR (#​15533)

• fix: decrement pending_count when form callback doesn't call submit() (#​15520)

v2.55.0

Compare Source

Minor Changes

• feat: page and layout params with matchers are now type narrowed in $app/types, leading to better type safety when working with params in $app/types, $app/state, and hooks. (#​15502)

v2.54.0

Compare Source

Minor Changes

• feat: allow error boundaries to catch errors on the server (#​15308)

Patch Changes

• chore: upgrade devalue (#​15535)

• fix: don't wait for remote functions that are not awaited in the template (#​15280)

• feat: allow resolve() to accept pathnames with a search string and/or hash (#​15458)

• chore: remove deprecation warnings for config.kit.files.* options when validating the Svelte config file (#​15482)

• fix: handles form target attribute in remote form redirects (#​15457)

v2.53.4

Compare Source

Patch Changes

• fix: avoid Vite warning about unknown codeSplitting option (#​15451)

v2.53.3

Compare Source

Patch Changes

• fix: prevent overlapping file metadata in remote functions form (faba869)

v2.53.2

Compare Source

Patch Changes

• fix: server-render nested form value sets (#​15378)

• fix: use deep partial types for form remote functions .value() and .set(...) (#​14837)

• fix: provide correct url info to remote functions (#​15418)

• fix: allow optional types for remote query/command/prerender functions (#​15293)

• fix: allow commands in more places (#​15288)

v2.53.1

Compare Source

Patch Changes

• fix: address warning about inlineDynamicImports when using Vite 8 (#​15403)

v2.53.0

Compare Source

Minor Changes

• feat: support Vite 8 (#​15024)

Patch Changes

• fix: remove event listeners on form attachment cleanup (#​15286)

• fix: apply queries refreshed in a form remote function when a redirect is thrown (#​15362)

v2.52.2

Compare Source

Patch Changes

• fix: validate form file information to prevent amplification attacks (3e607b3)

• chore: upgrade devalue and svelte (#​15339)

• fix: parse file offset table more strictly (f47c01b)

v2.52.0

Compare Source

Minor Changes

• feat: match function to map a path back to a route id and params (#​14997)

Patch Changes

• fix: respect scroll-margin when navigating to a url-supplied anchor (#​15246)

• fix: resolve will narrow types to follow trailing slash page settings (#​15027)

v2.51.0

Compare Source

Minor Changes

• feat: add scroll property to NavigationTarget in navigation callbacks (#​15248)

  Navigation callbacks (beforeNavigate, onNavigate, and afterNavigate) now include scroll position information via the scroll property on from and to targets:

  • from.scroll: The scroll position at the moment navigation was triggered
  • to.scroll: In beforeNavigate and onNavigate, this is populated for popstate navigations (back/forward) with the scroll position that will be restored, and null for other navigation types. In afterNavigate, this is always the final scroll position after navigation completed.

  This enables use cases like animating transitions based on the target scroll position when using browser back/forward navigation.

• feat: hydratable's injected script now works with CSP (#​15048)

Patch Changes

• fix: put preloads before styles (#​15232)

• fix: suppress false-positive inner content warning when children prop is forwarded to a child component (#​15269)

• fix: fetch not working when URL is same host but different than paths.base (#​15291)

• fix: navigate to hash link when base element is present (#​15236)

• fix: avoid triggering handleError when redirecting in a remote function (#​15222)

• fix: include test directory in generated tsconfig.json alongside existing tests entry (#​15254)

• fix: generate tsconfig.json using the value of kit.files.src (#​15253)

v2.50.2

Compare Source

Patch Changes

• fix: ensure inlined CSS follows paths.assets and paths.relative settings (#​15153)

• fix: emit script CSP nonces when unsafe-inline is present if strict-dynamic is also present (#​15221)

• fix: re-export browser/dev from esm-env (#​15206)

• fix: use validated args in batch resolver in both csr and ssr (#​15215)

• fix: ensure CSS inlining includes components that are conditionally rendered (#​15153)

• fix: only match rest params with matchers when the matcher matches (#​15216)

• fix: properly handle percent-encoded anchors (e.g. <a href="#sparkles-%E2%9C%A8">) during prerendering. (#​15231)

v2.50.1

Compare Source

Patch Changes

• fix: include hooks.server and hooks.universal as explicit Vite build inputs to ensure assets imported by hooks files are correctly discovered (#​15178)

• fix: improves fields type for generic components (#​14974)

• fix: preload links if href changes (#​15191)

v2.50.0

Compare Source

Minor Changes

• breaking: remove buttonProps from experimental remote form functions; use e.g. <button {...myForm.fields.action.as('submit', 'register')}>Register</button> button instead (#​15144)

v2.49.5

Compare Source

Patch Changes

• fix: avoid overriding Vite default base when running Vitest 4 (#​14866)

• fix: ensure url decoded pathnames are not mistaken as rerouted requests (d9ae9b0)

• fix: add length checks to remote forms (8ed8155)

v2.49.4

Compare Source

Patch Changes

• fix: support instrumentation for vite preview (#​15105)

• fix: support for URLSearchParams.has(name, value) overload (#​15076)

• fix: put forking behind experimental.forkPreloads (#​15135)

v2.49.3

Compare Source

Patch Changes

• fix: avoid false-positive Vite config overridden warning when using Vitest 4 (#​15121)

• fix: add typescript as an optional peer dependency (#​15074)

• fix: use hasOwn check when deep-setting object properties (#​15127)

v2.49.2

Compare Source

Patch Changes

• fix: Stop re-loading already-loaded CSS during server-side route resolution (#​15014)

• fix: posixify the instrumentation file import on Windows (#​14993)

• fix: Correctly handle shared memory when decoding binary form data (#​15028)

v2.49.1

Compare Source

Patch Changes

• fix: suppress state_referenced_locally warnings in .svelte-kit/generated/root.svelte (#​15013)

• fix: TypeError when doing response.clone() in page load (#​15005)

v2.49.0

Compare Source

Minor Changes

• feat: stream file uploads inside form remote functions allowing form data to be accessed before large files finish uploading (#​14775)

v2.48.8

Compare Source

Patch Changes

• breaking: invalid now must be imported from @sveltejs/kit (#​14768)

• breaking: remove submitter option from experimental form validate() method, always provide default submitter (#​14762)

v2.48.7

Compare Source

Patch Changes

• fix: allow multiple server-timing headers (#​14700)

• fix: allow access to root-level issues in schema-less forms (#​14893)

• fix: allow hosting hash-based apps from non-index.html files (#​14825)

v2.48.6

Compare Source

Patch Changes

• fix: clear issues upon passing validation (#​14683)

• fix: don't use fork of unrelated route (#​14947)

• fix: prevent type errors when optional @opentelemetry/api dependency isn't installed (#​14949)

• fix: preserve this when invoking standard validator (#​14943)

• fix: treat client/universal hooks as entrypoints for illegal server import detection (#​14876)

• fix: correct query .set and .refresh behavior in commands (#​14877)

• fix: improved the accuracy of the types of the output of field.as('...') (#​14908)

v2.48.5

Compare Source

Patch Changes

• fix: wait an extra microtask in dev before calling $_init_$ (#​14799)

• fix: discard preload fork before creating a new one (#​14865)

• fix: delete RemoteFormAllIssue, add path to RemoteFormIssue (#​14864)

v2.48.4

Compare Source

Patch Changes

• fix: adjust query's promise implementation to properly allow chaining (#​14859)

• fix: make prerender cache work, including in development (#​14860)

v2.48.3

Compare Source

Patch Changes

• fix: include hash when using resolve with hash routing enabled (#​14786)

• fix: afterNavigate callback not running after hydration when experimental async is enabled (#​14644)
  fix: Snapshot restore method not called after reload when experimental async is enabled

• fix: expose issue.path in .allIssues() (#​14784)

v2.48.2

Compare Source

Patch Changes

• fix: update DOM before running navigate callbacks (#​14829)

v2.48.1

Compare Source

Patch Changes

• fix: wait for commit promise instead of settled (#​14818)

v2.48.0

Compare Source

Minor Changes

• feat: use experimental fork API when available (#​14793)

Patch Changes

• fix: await for settled instead of tick in navigate (#​14800)

v2.47.3

Compare Source

Patch Changes

• fix: avoid hanging when error() is used while streaming promises from a server load function (#​14722)

• chore: treeshake load function code if we know it's unused (#​14764)

• fix: RecursiveFormFields type for recursive or unknown schemas (#​14734)

• fix: rework internal representation of form value to be $state (#​14771)

v2.47.2

Compare Source

Patch Changes

• fix: streamed promise not resolving when another load function returns a fast resolving promise (#​14753)

• chore: allow to run preflight validation only (#​14744)

• fix: update overload to set invalid type to schema input (#​14748)

v2.47.1

Compare Source

Patch Changes

• fix: allow read to be used at the top-level of remote function files (#​14672)

• fix: more robust remote files generation (#​14682)

v2.47.0

Compare Source

Minor Changes

• feat: add signal property to request (#​14715)

Patch Changes

• fix: resolve remote module syntax errors with trailing expressions (#​14728)

v2.46.5

Compare Source

Patch Changes

• fix: ensure form remote functions' fields.set triggers reactivity (#​14661)

v2.46.4

Compare Source

Patch Changes

• fix: prevent access of Svelte 5-only untrack function (#​14658)

v2.46.3

Compare Source

Patch Changes

• fix: merge field.set(...) calls (#​14651)

• fix: don't automatically reset form after an enhanced submission (#​14626)

• fix: normalize path strings when updating field values (#​14649)

v2.46.2

Compare Source

Patch Changes

• fix: prevent code execution order issues around SvelteKit's env modules (#​14637)

v2.46.1

Compare Source

Patch Changes

• fix: use $derived for form fields (#​14621)

• docs: remove @example blocks to allow docs to deploy (#​14636)

• fix: require a value with submit and hidden fields (#​14635)

• fix: delete hydration cache on effect teardown (#​14611)

v2.46.0

Compare Source

Minor Changes

• feat: imperative form validation (#​14624)

Patch Changes

• fix: wait a tick before collecting form data for validation (#​14631)

• fix: prevent code execution order issues around SvelteKit's env modules (#​14632)

v2.45.0

Compare Source

Minor Changes

• feat: form.for(id) now implicitly sets id on form object (#​14623)

Patch Changes

• fix: allow fetch in remote function without emitting a warning (#​14610)

v2.44.0

Compare Source

Minor Changes

• feat: expose event.route and event.url to remote functions (#​14606)

• breaking: update experimental form API (#​14481)

Patch Changes

• fix: don't crawl error responses during prerendering (#​14596)

v2.43.8

Compare Source

Patch Changes

• fix: HMR for query (#​14587)

• fix: avoid client modules while traversing dependencies to prevent FOUC during dev (#​14577)

• fix: skip prebundling of .remote.js files (#​14583)

• fix: more robust remote file pattern matching (#​14578)

v2.43.7

Compare Source

Patch Changes

• fix: correctly type the result of form remote functions that do not accept data (#​14573)

• fix: force remote module chunks to isolate themselves (#​14571)

v2.43.6

Compare Source

Patch Changes

• fix: ensure cache key is consistent between client/server (#​14563)

• fix: keep resolve relative to initial base during prerender (#​14533)

• fix: avoid including HEAD twice when an unhandled HTTP method is used in a request to a +server handler that has both a GET handler and a HEAD handler (#​14564)

• fix: smoothscroll to deep link (#​14569)

v2.43.5

Compare Source

Patch Changes

• fix: fall back to non-relative resolution when calling resolve(...) outside an event context (#​14532)

v2.43.4

Compare Source

Patch Changes

• fix: Webcontainer AsyncLocalStorage workaround (#​14526)

v2.43.3

Compare Source

Patch Changes

• fix: Webcontainer AsyncLocalStorage workaround (#​14521)

• fix: include the value of form submitters on form remote functions (#​14475)

v2.43.2

Compare Source

Patch Changes

• fix: ensure rendering starts off synchronously (#​14517)

• fix: keep serialized remote data alive until navigation (#​14508)

v2.43.1

Compare Source

Patch Changes

• fix: consistently use bare import for internals (#​14506)

v2.43.0

Compare Source

Minor Changes

• feat: experimental async SSR (#​14447)

Patch Changes

• fix: ensure __SVELTEKIT_PAYLOAD__.data is accessed safely (#​14491)

• fix: create separate cache entries for non-exported remote function queries (#​14499)

v2.42.2

Compare Source

Patch Changes

• fix: prevent loops in postbuild analysis phase (#​14450)

• fix: handle nested object fields in form data (#​14469)

• fix: robustify form helper types (#​14463)

• fix: avoid running the init hook during builds if there's nothing to prerender (#​14464)

• fix: ensure SSR rendering gets request store context (#​14476)

v2.42.1

Compare Source

Patch Changes

• fix: ensure environment setup is in its own chunk (#​14441)

v2.42.0

Compare Source

Minor Changes

• feat: enhance remote form functions with schema support, input and issues properties (#​14383)

• breaking: remote form functions get passed a parsed POJO instead of a FormData object now (#​14383)

v2.41.0

Compare Source

Minor Changes

• feat: add %sveltekit.version% to app.html (#​12132)

Patch Changes

• fix: allow remote functions to return custom types serialized with transport hooks (#​14435)

• fix: fulfil beforeNavigate complete when redirected (#​12896)

v2.40.0

Compare Source

Minor Changes

• feat: include event property on popstate/link/form navigation (#​14307)

Patch Changes

• fix: respect replaceState/keepFocus/noScroll when a navigation results in a redirect (#​14424)

• fix: invalidate preload cache when invalidateAll is true (#​14420)

v2.39.1

Compare Source

Patch Changes

• fix: more robust remote function code transformation (#​14418)

v2.39.0

Compare Source

Minor Changes

• feat: lazy discovery of remote functions (#​14293)

Patch Changes

• fix: layout load data not serialized on error page (#​14395)

• fix: fail prerendering when remote function fails (#​14365)

• fix: treat handle hook redirect as part of remote function call as json redirect (#​14362)

v2.38.1

Compare Source

Patch Changes

• fix: enable redirects from queries (#​14400)

• fix: remove empty nodes from serialized server load data (#​14404)

• fix: allow commands from within endpoints (#​14343)

v2.38.0

Compare Source

Minor Changes

• feat: add new remote function query.batch (#​14272)

v2.37.1

Compare Source

Patch Changes

• fix: serialize server load data before passing to universal load, to handle mutations and promises (#​14298)

• fix: resolve_route prevent dropping a trailing slash of id (#​14294)

• fix: assign correct status code to form submission error on the client (#​14345)

• fix: un-proxy form.result (#​14346)

v2.37.0

Compare Source

Minor Changes

• feat: automatically resolve query.refresh() promises on the server (#​14332)

• feat: allow query.set() to be called on the server (#​14304)

Patch Changes

• fix: disable CSRF checks in dev (#​14335)

• fix: allow redirects to external URLs from within form functions (#​14329)

• fix: add type definitions for query.set() method to override the value of a remote query function (#​14303)

• fix: ensure uniqueness of form.for(...) across form functions (#​14327)

v2.36.3

Compare Source

Patch Changes

• fix: bump devalue (#​14323)

• chore: consolidate dev checks to use esm-env instead of a __SVELTEKIT_DEV__ global (#​14308)

• fix: reset form inputs by default when using remote form functions (#​14322)

v2.36.2

Compare Source

Patch Changes

• chore: make config deprecation warnings more visible (#​14281)

• chore: remove redundant Not Found error message (#​14289)

• chore: deprecate csrf.checkOrigin in favour of csrf.trustedOrigins: ['*'] (#​14281)

v2.36.1

Compare Source

Patch Changes

• fix: ensure importing from $app/navigation works in test files (#​14195)

v2.36.0

Compare Source

Minor Changes

• feat: add csrf.trustedOrigins configuration (#​14021)

Patch Changes

• fix: correctly decode custom types streamed from a server load function (#​14261)

• fix: add trailing slash pathname when generating typed routes (#​14065)

v2.35.0

Compare Source

Minor Changes

• feat: better server-side error logging (#​13990)

Patch Changes

• fix: ensure static error page is loaded correctly for custom user errors (#​13952)

v2.34.1

Compare Source

Patch Changes

• fix: support multiple cookies with the same name across different paths and domains (b2c5d02)

• fix: add link header when preloading font (#​14200)

• fix: cookies.get(...) returns undefined for a just-deleted cookie (b2c5d02)

• fix: load env before prerender (c5f7139)

v2.34.0

Compare Source

Minor Changes

• feat: allow dynamic env access during prerender (#​14243)

Patch Changes

• fix: clone fetch responses so that headers are mutable (#​13942)

• fix: se

✂ Note

PR body was truncated to here.