diff --git a/meta/recipes-devtools/python/python3/CVE-2026-7210.patch b/meta/recipes-devtools/python/python3/CVE-2026-7210.patch new file mode 100644 index 0000000000..337130d9b7 --- /dev/null +++ b/meta/recipes-devtools/python/python3/CVE-2026-7210.patch @@ -0,0 +1,136 @@ +From a7fafeebaf33995556a37e9eec4f6a6bcfce2e67 Mon Sep 17 00:00:00 2001 +From: Stan Ulbrych +Date: Sun, 10 May 2026 18:36:26 +0100 +Subject: [PATCH] gh-149018: Use `XML_SetHashSalt16Bytes` in `pyexpat`/`_elementtree` when possible (#149023) + +CVE-2026-7210 is a hash-flooding denial-of-service vulnerability in +Python's XML parsing modules (xml.parsers.expat, xml.etree.ElementTree). +An attacker can craft XML input that forces O(n²) hash collisions in +libexpat's internal name dictionary, causing excessive CPU consumption. + +The previous mitigation seeded libexpat's hash function with only 4 +bytes of entropy, which is insufficient against a determined attacker. +This patch upgrades to XML_SetHashSalt16Bytes (libexpat >= 2.8.0), +providing a full 16-byte secret. Older expat versions fall back +gracefully to the legacy XML_SetHashSalt via a runtime NULL check. + +NOTE: CVE-2026-7210 full mitigation requires the companion + expat CVE-2026-41080 patch (raises expat to >= 2.8.0 API) + +CVE: CVE-2026-7210 +Upstream-Status: Backport [https://github.com/python/cpython/commit/24b8f12544468e4cedf5bfbe25442fcd495391e4] + +Signed-off-by: Amaury Couderc +--- + Include/internal/pycore_pyhash.h | 8 +++++--- + Include/pyexpat.h | 3 +++ + .../2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst | 3 +++ + Modules/_elementtree.c | 8 ++++++-- + Modules/pyexpat.c | 10 +++++++++- + 5 files changed, 26 insertions(+), 6 deletions(-) + create mode 100644 Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst + +diff --git a/Include/internal/pycore_pyhash.h b/Include/internal/pycore_pyhash.h +index 84cb72fa6fd..3056dc44cc0 100644 +--- a/Include/internal/pycore_pyhash.h ++++ b/Include/internal/pycore_pyhash.h +@@ -27,14 +27,14 @@ _Py_HashPointerRaw(const void *ptr) + * pppppppp ssssssss ........ fnv -- two Py_hash_t + * k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t + * ........ ........ ssssssss djbx33a -- 16 bytes padding + one Py_hash_t +- * ........ ........ eeeeeeee pyexpat XML hash salt ++ * eeeeeeee eeeeeeee eeeeeeee pyexpat XML hash salt + * + * memory layout on 32 bit systems + * cccccccc cccccccc cccccccc uc + * ppppssss ........ ........ fnv -- two Py_hash_t + * k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t (*) + * ........ ........ ssss.... djbx33a -- 16 bytes padding + one Py_hash_t +- * ........ ........ eeee.... pyexpat XML hash salt ++ * eeeeeeee eeeeeeee eeee.... pyexpat XML hash salt + * + * (*) The siphash member may not be available on 32 bit platforms without + * an unsigned int64 data type. +@@ -58,7 +58,9 @@ typedef union { + Py_hash_t suffix; + } djbx33a; + struct { +- unsigned char padding[16]; ++ /* 16 bytes for XML_SetHashSalt16Bytes */ ++ uint8_t hashsalt16[16]; ++ /* 4/8 bytes for legacy XML_SetHashSalt */ + Py_hash_t hashsalt; + } expat; + } _Py_HashSecret_t; +diff --git a/Include/pyexpat.h b/Include/pyexpat.h +index 04548b7684a..d28d6828975 100644 +--- a/Include/pyexpat.h ++++ b/Include/pyexpat.h +@@ -57,6 +57,9 @@ struct PyExpat_CAPI + XML_Parser parser, unsigned long long activationThresholdBytes); + XML_Bool (*SetAllocTrackerMaximumAmplification)( + XML_Parser parser, float maxAmplificationFactor); ++ /* might be NULL for expat < 2.8.0 */ ++ XML_Bool (*SetHashSalt16Bytes)( ++ XML_Parser parser, const uint8_t entropy[16]); + /* always add new stuff to the end! */ + }; + +diff --git a/Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst b/Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst +new file mode 100644 +index 00000000000..d1b5b368684 +--- /dev/null ++++ b/Misc/NEWS.d/next/Security/2026-04-26-19-30-45.gh-issue-149018.a9SqWb.rst +@@ -0,0 +1,3 @@ ++Improved protection against XML hash-flooding attacks in ++:mod:`xml.parsers.expat` and :mod:`xml.etree.ElementTree` when Python is ++compiled with libExpat 2.8.0 or later. +diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c +index 7ca03f1561b..44d59fcb806 100644 +--- a/Modules/_elementtree.c ++++ b/Modules/_elementtree.c +@@ -3724,8 +3724,12 @@ _elementtree_XMLParser___init___impl(XMLParserObject *self, PyObject *target, + PyErr_NoMemory(); + return -1; + } +- /* expat < 2.1.0 has no XML_SetHashSalt() */ +- if (EXPAT(st, SetHashSalt) != NULL) { ++ // Prefer 16-byte entropy, only expat >= 2.8.0. See gh-149018 ++ if (EXPAT(st, SetHashSalt16Bytes) != NULL) { ++ EXPAT(st, SetHashSalt16Bytes)(self->parser, ++ _Py_HashSecret.expat.hashsalt16); ++ } ++ else if (EXPAT(st, SetHashSalt) != NULL) { + EXPAT(st, SetHashSalt)(self->parser, + (unsigned long)_Py_HashSecret.expat.hashsalt); + } +diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c +index f82f8456e48..437fd5fb61a 100644 +--- a/Modules/pyexpat.c ++++ b/Modules/pyexpat.c +@@ -1416,7 +1416,11 @@ newxmlparseobject(pyexpat_state *state, const char *encoding, + Py_DECREF(self); + return NULL; + } +-#if XML_COMBINED_VERSION >= 20100 ++#if defined(XML_BACKPORT_SET_HASH_SALT_16_BYTES) \ ++ || XML_COMBINED_VERSION >= 20800 ++ /* This feature was added upstream in libexpat 2.8.0. */ ++ XML_SetHashSalt16Bytes(self->itself, _Py_HashSecret.expat.hashsalt16); ++#elif XML_COMBINED_VERSION >= 20100 + /* This feature was added upstream in libexpat 2.1.0. */ + XML_SetHashSalt(self->itself, + (unsigned long)_Py_HashSecret.expat.hashsalt); +@@ -2310,6 +2313,12 @@ pyexpat_exec(PyObject *mod) + #else + capi->SetHashSalt = NULL; + #endif ++#if defined(XML_BACKPORT_SET_HASH_SALT_16_BYTES) \ ++ || XML_COMBINED_VERSION >= 20800 ++ capi->SetHashSalt16Bytes = XML_SetHashSalt16Bytes; ++#else ++ capi->SetHashSalt16Bytes = NULL; ++#endif + #if XML_COMBINED_VERSION >= 20600 + capi->SetReparseDeferralEnabled = XML_SetReparseDeferralEnabled; + #else diff --git a/meta/recipes-devtools/python/python3_3.14.5.bb b/meta/recipes-devtools/python/python3_3.14.5.bb index ed413dc1fe..83f6bf426c 100644 --- a/meta/recipes-devtools/python/python3_3.14.5.bb +++ b/meta/recipes-devtools/python/python3_3.14.5.bb @@ -36,6 +36,7 @@ SRC_URI = "http://www.python.org/ftp/python/${PV}/Python-${PV}.tar.xz \ file://0001-test_only_active_thread-skip-problematic-test.patch \ file://0001-prefer-valid-entrypoints.patch \ file://0001-Fix-ThreadingMock-call-count-race-condition.patch \ + file://CVE-2026-7210.patch \ " SRC_URI:append:class-native = " \ file://0001-Lib-sysconfig.py-use-prefix-value-from-build-configu.patch \