diff --git a/CMakeLists.txt b/CMakeLists.txt
index 483e406a02..84611ae9a1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3340,6 +3340,39 @@ if(WOLFSSL_FALLBACK_SCSV)
         )
 endif()
 
+add_option("WOLFSSL_CXET_HFT"
+    "Enable the CXET Linux x86-64 HFT transport profile (default: disabled)"
+    "no" "yes;no")
+if(WOLFSSL_CXET_HFT)
+    if(NOT CMAKE_SYSTEM_NAME STREQUAL "Linux")
+        message(FATAL_ERROR "WOLFSSL_CXET_HFT supports Linux only")
+    endif()
+    if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "^(x86_64|amd64|AMD64)$")
+        message(FATAL_ERROR "WOLFSSL_CXET_HFT supports x86-64 only")
+    endif()
+    if(NOT CMAKE_C_COMPILER_ID MATCHES "^(GNU|Clang)$")
+        message(FATAL_ERROR
+            "WOLFSSL_CXET_HFT requires GCC or Clang atomic builtins")
+    endif()
+    if(WOLFSSL_SINGLE_THREADED)
+        message(FATAL_ERROR
+            "WOLFSSL_CXET_HFT requires normal threaded lifetime handling")
+    endif()
+    if(WOLFSSL_DTLS OR WOLFSSL_DTLS13)
+        message(FATAL_ERROR "WOLFSSL_CXET_HFT does not support DTLS")
+    endif()
+    if(WOLFSSL_POSTAUTH)
+        message(FATAL_ERROR
+            "WOLFSSL_CXET_HFT does not support post-handshake authentication")
+    endif()
+    if(WOLFSSL_QUIC)
+        message(FATAL_ERROR "WOLFSSL_CXET_HFT does not support QUIC")
+    endif()
+
+    force_option(WOLFSSL_WRITEDUP "yes")
+    list(APPEND WOLFSSL_DEFINITIONS "-DWOLFSSL_CXET_HFT")
+endif()
+
 add_option("WOLFSSL_WRITEDUP"
     "Enable write duplication of SSL objects (default: disabled)"
     "no" "yes;no")
diff --git a/cmake/options.h.in b/cmake/options.h.in
index 431f2545d6..685940b4fb 100644
--- a/cmake/options.h.in
+++ b/cmake/options.h.in
@@ -497,6 +497,14 @@ extern "C" {
 #cmakedefine HAVE_FALLBACK_SCSV
 #undef HAVE_WRITE_DUP
 #cmakedefine HAVE_WRITE_DUP
+#undef WOLFSSL_CXET_HFT
+#cmakedefine WOLFSSL_CXET_HFT
+
+#undef WOLFSSL_AESNI
+#cmakedefine WOLFSSL_AESNI
+
+#undef WOLFSSL_SP_X86_64_ASM
+#cmakedefine WOLFSSL_SP_X86_64_ASM
 #undef ATOMIC_USER
 #cmakedefine ATOMIC_USER
 #undef WOLFSSL_USE_RWLOCK
diff --git a/doc/cxet-hft-profile.md b/doc/cxet-hft-profile.md
new file mode 100644
index 0000000000..62c730a7cb
--- /dev/null
+++ b/doc/cxet-hft-profile.md
@@ -0,0 +1,38 @@
+# CXET HFT transport profile
+
+`WOLFSSL_CXET_HFT` is an opt-in profile for the CXET Linux x86-64 transport
+build. It preserves the normal wolfSSL certificate, SNI, hostname-verification,
+record, cipher and socket-I/O behavior.
+
+The profile changes only the bounded read-to-write mailbox used after
+`wolfSSL_write_dup()`:
+
+- fatal read errors and close notifications use acquire/release atomics;
+- TLS 1.3 `KeyUpdate(update_requested)` uses a one-byte atomic mailbox;
+- the existing mutex remains the owner of cold duplicate lifetime/refcount
+  destruction.
+
+The application must quiesce both duplicate sides before either side is freed.
+The profile does not make concurrent destruction safe.
+
+The CMake profile is fail-closed. It supports Linux x86-64 with GCC or Clang,
+enables `WOLFSSL_WRITEDUP`, and rejects `SINGLE_THREADED`, DTLS, QUIC and TLS
+1.3 post-handshake authentication.
+
+Configure with:
+
+```sh
+cmake -S . -B build-cxet \
+  -DWOLFSSL_CXET_HFT=yes \
+  -DWOLFSSL_DTLS=no \
+  -DWOLFSSL_DTLS13=no \
+  -DWOLFSSL_POSTAUTH=no \
+  -DWOLFSSL_QUIC=no
+```
+
+The profile build exports `wolfSSL_CXET_hft_profile_version()` and defines
+`WOLFSSL_CXET_HFT` in generated `wolfssl/options.h`. CXET's build/staging gates
+require both markers and reject a profile-off or stale shared library.
+
+This profile is a latency candidate until the CXET end-to-end transport gates
+have been run. The source change alone is not evidence of an improvement.
diff --git a/src/ssl.c b/src/ssl.c
index 5368c107fa..26c56bc349 100644
--- a/src/ssl.c
+++ b/src/ssl.c
@@ -1042,6 +1042,12 @@ WOLFSSL* wolfSSL_write_dup(WOLFSSL* ssl)
 */
 int NotifyWriteSide(WOLFSSL* ssl, int err)
 {
+#ifdef WOLFSSL_CXET_HFT
+    WOLFSSL_ENTER("NotifyWriteSide");
+
+    WriteDupStoreError(ssl->dupWrite, err);
+    return 0;
+#else
     int ret;
 
     WOLFSSL_ENTER("NotifyWriteSide");
@@ -1053,6 +1059,7 @@ int NotifyWriteSide(WOLFSSL* ssl, int err)
     }
 
     return ret;
+#endif
 }
 
 
@@ -5898,6 +5905,13 @@ const char* wolfSSL_lib_version(void)
     return LIBWOLFSSL_VERSION_STRING;
 }
 
+#ifdef WOLFSSL_CXET_HFT
+unsigned int wolfSSL_CXET_hft_profile_version(void)
+{
+    return WOLFSSL_CXET_HFT_PROFILE_VERSION;
+}
+#endif
+
 #ifdef OPENSSL_EXTRA
 #if defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER >= 0x10100000L
 const char* wolfSSL_OpenSSL_version(int a)
diff --git a/src/ssl_api_rw.c b/src/ssl_api_rw.c
index b1621019f1..175a6836b5 100644
--- a/src/ssl_api_rw.c
+++ b/src/ssl_api_rw.c
@@ -70,6 +70,16 @@ static int wolfSSL_write_internal(WOLFSSL* ssl, const void* data, size_t sz)
      * with handling async data and other edge case errors. */
     if (ssl->dupWrite != NULL && ssl->error == 0) {
         int dupErr = 0;   /* local copy */
+#ifdef WOLFSSL_CXET_HFT
+        dupErr = WriteDupLoadError(ssl->dupWrite);
+#ifdef WOLFSSL_TLS13
+        if (IsAtLeastTLSv1_3(ssl->version)) {
+            /* The read side publishes only a bounded KeyUpdate bit. */
+            ssl->keys.keyUpdateRespond |=
+                WriteDupTakeKeyUpdate(ssl->dupWrite);
+        }
+#endif /* WOLFSSL_TLS13 */
+#else
         /* Lock ssl->dupWrite to gather what needs to be done. */
         if (wc_LockMutex(&ssl->dupWrite->dupMutex) != 0)
             return BAD_MUTEX_E;
@@ -145,6 +155,7 @@ static int wolfSSL_write_internal(WOLFSSL* ssl, const void* data, size_t sz)
         }
 #endif /* WOLFSSL_TLS13 */
         wc_UnLockMutex(&ssl->dupWrite->dupMutex);
+#endif /* WOLFSSL_CXET_HFT */
 
         if (dupErr != 0) {
             WOLFSSL_MSG("Write dup error from other side");
diff --git a/src/tls13.c b/src/tls13.c
index 5b785e7eb4..70b456c8a3 100644
--- a/src/tls13.c
+++ b/src/tls13.c
@@ -12612,10 +12612,14 @@ static int DoTls13KeyUpdate(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
 #if defined(HAVE_WRITE_DUP) && defined(WOLFSSL_TLS13)
         /* Read side cannot write; delegate the response to the write side. */
         if (ssl->dupWrite != NULL && ssl->dupSide == READ_DUP_SIDE) {
+#ifdef WOLFSSL_CXET_HFT
+            WriteDupPostKeyUpdate(ssl->dupWrite);
+#else
             if (wc_LockMutex(&ssl->dupWrite->dupMutex) != 0)
                 return BAD_MUTEX_E;
             ssl->dupWrite->keyUpdateRespond = 1;
             wc_UnLockMutex(&ssl->dupWrite->dupMutex);
+#endif
             ssl->keys.keyUpdateRespond = 0;
             return 0;
         }
diff --git a/wolfssl/internal.h b/wolfssl/internal.h
index f351093c34..66af0ce01e 100644
--- a/wolfssl/internal.h
+++ b/wolfssl/internal.h
@@ -5998,7 +5998,7 @@ typedef struct BuildMsgArgs {
     typedef struct WriteDup {
         wolfSSL_Mutex   dupMutex;       /* field access mutex */
         int             dupCount;       /* reference count */
-        int             dupErr;         /* under dupMutex, pass to other side */
+        int             dupErr;         /* pass fatal state to write side */
 #ifdef WOLFSSL_DTLS13
         struct Dtls13RecordNumber* sendAckList; /* ownership transferred */
         /* Key update ACK tracking: write side stores the (epoch, seq) of its
@@ -6032,13 +6032,45 @@ typedef struct BuildMsgArgs {
 #ifdef WOLFSSL_TLS13
         /* TLS 1.3 (and DTLS 1.3): read side received a KeyUpdate(update_requested)
          * but cannot send the response; write side handles it. */
+#ifdef WOLFSSL_CXET_HFT
+        byte keyUpdateRespond;          /* atomic CXET read-to-write mailbox */
+#else
         WC_BITFIELD keyUpdateRespond:1; /* write side must send a KeyUpdate response */
+#endif
 #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
         WC_BITFIELD postHandshakeAuthPending:1; /* write side must respond */
 #endif /* WOLFSSL_POST_HANDSHAKE_AUTH */
 #endif /* WOLFSSL_TLS13 */
     } WriteDup;
 
+#ifdef WOLFSSL_CXET_HFT
+    static WC_INLINE int WriteDupLoadError(const WriteDup* state)
+    {
+        return __atomic_load_n(&state->dupErr, __ATOMIC_ACQUIRE);
+    }
+
+    static WC_INLINE void WriteDupStoreError(WriteDup* state, int error)
+    {
+        __atomic_store_n(&state->dupErr, error, __ATOMIC_RELEASE);
+    }
+
+#ifdef WOLFSSL_TLS13
+    static WC_INLINE byte WriteDupTakeKeyUpdate(WriteDup* state)
+    {
+        if (__atomic_load_n(&state->keyUpdateRespond, __ATOMIC_ACQUIRE) == 0)
+            return 0;
+
+        return __atomic_exchange_n(&state->keyUpdateRespond, 0,
+            __ATOMIC_ACQ_REL);
+    }
+
+    static WC_INLINE void WriteDupPostKeyUpdate(WriteDup* state)
+    {
+        __atomic_store_n(&state->keyUpdateRespond, 1, __ATOMIC_RELEASE);
+    }
+#endif /* WOLFSSL_TLS13 */
+#endif /* WOLFSSL_CXET_HFT */
+
     WOLFSSL_LOCAL void FreeWriteDup(WOLFSSL* ssl);
     WOLFSSL_LOCAL int  NotifyWriteSide(WOLFSSL* ssl, int err);
 #endif /* HAVE_WRITE_DUP */
diff --git a/wolfssl/ssl.h b/wolfssl/ssl.h
index 423f027c74..4fea56f839 100644
--- a/wolfssl/ssl.h
+++ b/wolfssl/ssl.h
@@ -1450,6 +1450,11 @@ WOLFSSL_API WOLFSSL_X509_VERIFY_PARAM* wolfSSL_get0_param(WOLFSSL* ssl);
 WOLFSSL_API int wolfSSL_CTX_set1_param(WOLFSSL_CTX* ctx, WOLFSSL_X509_VERIFY_PARAM *vpm);
 WOLFSSL_API int  wolfSSL_is_server(WOLFSSL* ssl);
 WOLFSSL_API WOLFSSL* wolfSSL_write_dup(WOLFSSL* ssl);
+#define WOLFSSL_CXET_HFT_PROFILE_VERSION 1U
+#ifdef WOLFSSL_CXET_HFT
+WOLFSSL_ABI WOLFSSL_API unsigned int
+    wolfSSL_CXET_hft_profile_version(void);
+#endif
 WOLFSSL_ABI WOLFSSL_API int  wolfSSL_set_fd(WOLFSSL* ssl, int fd);
 #ifdef WOLFSSL_DTLS
 WOLFSSL_API int wolfSSL_set_dtls_fd_connected(WOLFSSL* ssl, int fd);
diff --git a/wolfssl/wolfcrypt/settings.h b/wolfssl/wolfcrypt/settings.h
index 49ea49b0b8..bfd89e5e16 100644
--- a/wolfssl/wolfcrypt/settings.h
+++ b/wolfssl/wolfcrypt/settings.h
@@ -3290,6 +3290,27 @@
     #error "WRITE DUP and SECURE RENEGOTIATION cannot both be on"
 #endif
 
+#ifdef WOLFSSL_CXET_HFT
+    #if !defined(__GNUC__) && !defined(__clang__)
+        #error "WOLFSSL_CXET_HFT requires GCC or Clang atomic builtins"
+    #endif
+    #ifdef SINGLE_THREADED
+        #error "WOLFSSL_CXET_HFT requires threaded lifetime handling"
+    #endif
+    #ifndef HAVE_WRITE_DUP
+        #error "WOLFSSL_CXET_HFT requires HAVE_WRITE_DUP"
+    #endif
+    #if defined(WOLFSSL_DTLS) || defined(WOLFSSL_DTLS13)
+        #error "WOLFSSL_CXET_HFT does not support DTLS"
+    #endif
+    #ifdef WOLFSSL_POST_HANDSHAKE_AUTH
+        #error "WOLFSSL_CXET_HFT does not support post-handshake authentication"
+    #endif
+    #ifdef WOLFSSL_QUIC
+        #error "WOLFSSL_CXET_HFT does not support QUIC"
+    #endif
+#endif /* WOLFSSL_CXET_HFT */
+
 #ifdef WOLFSSL_SGX
     #ifdef _MSC_VER
         #define NO_RC4