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Update urllib3 lock resolution to 2.7.0 for GHSA-mf9v-mfxr-j63j#1

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Update urllib3 lock resolution to 2.7.0 for GHSA-mf9v-mfxr-j63j#1
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Copilot AI commented May 30, 2026

This addresses the high-severity Dependabot alert for urllib3 (GHSA-mf9v-mfxr-j63j / CVE-2026-44432), where pre-2.7.0 streaming decompression paths can trigger excessive resource use. The fix is to move to the lowest patched version (2.7.0) with minimal dependency surface change.

  • Dependency remediation

    • Regenerated uv.lock via project tooling so urllib3 now resolves to 2.7.0 (from vulnerable 2.6.3).
  • Scope and blast radius

    • Change is lockfile-scoped (uv.lock) with no application code modifications.
  • Reachability Assessment

    • Searched for vulnerable-path usage (HTTPResponse.read(amt=...), HTTPResponse.stream(amt=...), HTTPResponse.drain_conn(), direct urllib3 streaming/brotli usage).
    • No reachable call sites found in repository code; matches were only dependency metadata.
    • Assessment: not actively reachable in current code paths; update is primarily scanner/compliance hardening.
    • Confidence: high.
# uv.lock (resolved package)
name = "urllib3"
version = "2.7.0"
Original prompt

This section details the Dependabot vulnerability alert you should resolve

<alert_title>urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API</alert_title>
<alert_description>### Impact

urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once.

urllib3 can perform decompression based on the HTTP Content-Encoding header (e.g., gzip, deflate, br, or zstd). When using the streaming API since version 2.6.0, the library decompresses only the necessary bytes, enabling partial content consumption.

However, urllib3 before version 2.7.0 could still decompress the whole response instead of the requested portion in two cases:

  1. During the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library.
  2. When HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here).

These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data; CWE-409) on the client side.

Affected usages

Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected when streaming compressed responses from untrusted sources in either of these cases, unless decompression is explicitly disabled:

  1. A response encoded with br is read incrementally with at least two HTTPResponse.read(amt=N) or HTTPResponse.stream(amt=N) calls while using the official Brotli library.
  2. HTTPResponse.drain_conn() is called after response decompression has already started.

Remediation

Upgrade to at least urllib3 version 2.7.0 in which the library:

  1. Is more efficient for reads with Brotli.
  2. Always skips decompression for HTTPResponse.drain_conn().

If upgrading is not immediately possible, the following workarounds may reduce exposure in specific cases:

  1. For the Brotli-specific issue only, switch from brotli to brotlicffi until you can upgrade urllib3; the official Brotli package is affected because of [Python] output_buffer_limit is not fully respected google/brotli#1396.
  2. If your code explicitly calls HTTPResponse.drain_conn(), call HTTPResponse.close() instead when connection reuse is not important.

Credits

The Brotli-specific issue was reported by @kimkou2024.
HTTPResponse.drain_conn() inefficiency was reported by @Cycloctane.</alert_description>

high
GHSA-mf9v-mfxr-j63j, CVE-2026-44432
urllib3
pip
<vulnerable_versions>= 2.6.3</vulnerable_versions>
<patched_version>2.7.0</patched_version>
<manifest_path>uv.lock</manifest_path>

https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j https://nvd.nist.gov/vuln/detail/CVE-2026-44432 https://github.com/advisories/GHSA-mf9v-mfxr-j63j

<task_instructions>Resolve this alert by updating the affected package to a non-vulnerable version. Prefer the lowest non-vulnerable version (see the patched_version field above) over the latest to minimize breaking changes. Include a Reachability Assessment section in the PR description. Review the alert_description field to understand which APIs, features, or configurations are affected, then search the codebase for usage of those specific items. If the vulnerable code path is reachable, explain how (which files, APIs, or call sites use the affected functionality) and note that the codebase is actively exposed to this vulnerability. If the vulnerable code path is not reachable, explain why (e.g. the affected API is never called, the vulnerable configuration is not used) and note that the update is primarily to satisfy vulnerability scanners rather than to address an active risk. If the advisory is too vague to determine reachability (e.g. 'improper input validation' with no specific API named), state that reachability could not be determined and explain why. Include a confidence level in the reachability assessment (e.g. high confidence if the advisory names a specific API and you confirmed it is or is not called, low confidence if the usage is indirect and hard to trace). If no patched version is available, check the alert_description field for a Workarounds section — the advisory may describe configuration changes or usage patterns that mitigate the vulnerability without a version update. If a workaround is available, apply it and leave a code comment referencing the advisory identi...

  • Resolves developmentAC/myQR alert #54

Copilot AI changed the title [WIP] Fix urllib3 decompression-bomb safeguards in streaming API Update urllib3 lock resolution to 2.7.0 for GHSA-mf9v-mfxr-j63j May 30, 2026
Copilot AI requested a review from obonhamcarter May 30, 2026 08:28
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