Amazon Linux 2 Security Advisory: ALAS2-2026-3827
Advisory Released Date: 2026-08-04
Advisory Updated Date: 2026-08-04
libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking.
By supplying an overly long input line, an attacker can overflow internal buffers (command, arg, and argv) during input parsing. This results in memory corruption within the stack frame.
Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process.
This issue has been fixed in the commit c2e233fc.
NOTE:
The maintainers of this project did not agree that this issue is a vulnerability and considered it a bug. (CVE-2026-11979)
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 ALAS2-2026-3827 to update your system.
aarch64:
libxml2-2.9.1-6.amzn2.5.26.aarch64
libxml2-devel-2.9.1-6.amzn2.5.26.aarch64
libxml2-static-2.9.1-6.amzn2.5.26.aarch64
libxml2-python-2.9.1-6.amzn2.5.26.aarch64
libxml2-debuginfo-2.9.1-6.amzn2.5.26.aarch64
i686:
libxml2-2.9.1-6.amzn2.5.26.i686
libxml2-devel-2.9.1-6.amzn2.5.26.i686
libxml2-static-2.9.1-6.amzn2.5.26.i686
libxml2-python-2.9.1-6.amzn2.5.26.i686
libxml2-debuginfo-2.9.1-6.amzn2.5.26.i686
src:
libxml2-2.9.1-6.amzn2.5.26.src
x86_64:
libxml2-2.9.1-6.amzn2.5.26.x86_64
libxml2-devel-2.9.1-6.amzn2.5.26.x86_64
libxml2-static-2.9.1-6.amzn2.5.26.x86_64
libxml2-python-2.9.1-6.amzn2.5.26.x86_64
libxml2-debuginfo-2.9.1-6.amzn2.5.26.x86_64