CVE-2026-11979
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk4th percentile - higher than 4% of all known CVEs
Summary
Multiple stack-based buffer overflows were discovered in the xmlcatalog utility of libxml2 when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking. Supplying an overly long input line can overflow internal buffers (command, arg, and argv) during input parsing.
Risk Assessment
Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process. This poses a risk to organizations if xmlcatalog is used in production environments or automation scripts.
Recommendation
Update libxml2 to a version containing the fix from commit c2e233fc. If an update is not possible, avoid using the xmlcatalog utility in --shell mode with untrusted input.
Original NVD description (English source)
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.