ALAS2023-2026-3122

References: CVE-2026-74860  CVE-2026-86137  CVE-2026-86138  CVE-2026-86140  CVE-2026-86142  CVE-2026-86143  CVE-2026-86144 
FAQs regarding Amazon Linux ALAS/CVE Severity

Issue Overview:

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)

Issue Correction:
Run dnf update libxml2 --releasever 2023.12.20260928 or dnf update --advisory ALAS2023-2026-3122 --releasever 2023.12.20260928 to update your system.
More information on how to update your system can be found on this page: Amazon Linux 2023 documentation

New Packages:

aarch64:
    libxml2-debugsource-2.10.4-1.amzn2023.0.21.aarch64
    libxml2-static-2.10.4-1.amzn2023.0.21.aarch64
    python3-libxml2-debuginfo-2.10.4-1.amzn2023.0.21.aarch64
    libxml2-debuginfo-2.10.4-1.amzn2023.0.21.aarch64
    libxml2-devel-2.10.4-1.amzn2023.0.21.aarch64
    python3-libxml2-2.10.4-1.amzn2023.0.21.aarch64
    libxml2-2.10.4-1.amzn2023.0.21.aarch64

src:
    libxml2-2.10.4-1.amzn2023.0.21.src

x86_64:
    libxml2-debugsource-2.10.4-1.amzn2023.0.21.x86_64
    libxml2-static-2.10.4-1.amzn2023.0.21.x86_64
    python3-libxml2-debuginfo-2.10.4-1.amzn2023.0.21.x86_64
    python3-libxml2-2.10.4-1.amzn2023.0.21.x86_64
    libxml2-devel-2.10.4-1.amzn2023.0.21.x86_64
    libxml2-2.10.4-1.amzn2023.0.21.x86_64
    libxml2-debuginfo-2.10.4-1.amzn2023.0.21.x86_64