Amazon Linux 2 (EOS) Security Advisory: ALAS2-2026-3940
Advisory Released Date: 2026-09-28
Advisory Updated Date: 2026-09-28
FAQs regarding Amazon Linux ALAS/CVE Severity
A flaw was found in libxml2 with Python bindings enabled. A remote attacker could exploit this vulnerability by providing a specially crafted XML document containing a Document Type Definition (DTD) with enumerated attribute values. This triggers a double-free error in the SAX attributeDecl callback handler, where a string is freed twice. This flaw can lead to a denial of service (DoS) due to a reproducible crash in Python applications using the libxml2 SAX bindings. (CVE-2026-74860)
In libxml2 before 2.15.4, xmlFAParsePosCharGroup has an out-of-bounds read, aka an out-of-bounds read in the NXT macro in xmlregexp. (CVE-2026-86137)
In libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based buffer overflow. (CVE-2026-86138)
In libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow. (CVE-2026-86140)
In libxml2 before 2.15.4, there is a heap-based buffer overflow in xmlXPtrEvalXPtrPart because of xmlXPtrEval xpointer length saturation. (CVE-2026-86142)
In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback. (CVE-2026-86143)
In xinclude in libxml2 before 2.15.4, xmlXIncludeProcess and xmlXIncludeProcessTree do not propagate parseFlags. This has security relevance for, for example, the XML_PARSE_NONET flag, if (without it) a custom resource loader accesses the internet and triggers XML external entity injection, SSRF, or a denial of service (e.g., for an attacker-controlled internet resource that is intentionally slow). (CVE-2026-86144)
Affected Packages:
libxml2
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update libxml2 or yum update --advisory ALAS2-2026-3940 to update your system.
aarch64:
libxml2-2.9.1-6.amzn2.5.27.aarch64
libxml2-devel-2.9.1-6.amzn2.5.27.aarch64
libxml2-static-2.9.1-6.amzn2.5.27.aarch64
libxml2-python-2.9.1-6.amzn2.5.27.aarch64
libxml2-debuginfo-2.9.1-6.amzn2.5.27.aarch64
i686:
libxml2-2.9.1-6.amzn2.5.27.i686
libxml2-devel-2.9.1-6.amzn2.5.27.i686
libxml2-static-2.9.1-6.amzn2.5.27.i686
libxml2-python-2.9.1-6.amzn2.5.27.i686
libxml2-debuginfo-2.9.1-6.amzn2.5.27.i686
src:
libxml2-2.9.1-6.amzn2.5.27.src
x86_64:
libxml2-2.9.1-6.amzn2.5.27.x86_64
libxml2-devel-2.9.1-6.amzn2.5.27.x86_64
libxml2-static-2.9.1-6.amzn2.5.27.x86_64
libxml2-python-2.9.1-6.amzn2.5.27.x86_64
libxml2-debuginfo-2.9.1-6.amzn2.5.27.x86_64