CVE-2026-11979
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.
CSIRTS triage
- What
- Stack-based buffer overflow in libxml2.
- Who is affected
- Users of libxml2 are affected.
- Urgency
- Remediation is unknown due to lack of severity information.
- Action
- Monitor for updates regarding this vulnerability.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 4% of all EPSS-scored CVEs.
Advisory coverage (2)
- highCVE-2026-11979: libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when …nvd · 2026-06-29
- unknownCVE-2026-11979: Stack-Based Buffer Overflow in libxml2msrc · 2026-06-09
External references
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