CVE-2026-11979: CWE-121: Stack-based Buffer Overflow in xmlsoft libxml2
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.
AI Analysis
Technical Summary
The xmlcatalog utility in libxml2 is vulnerable to stack-based buffer overflows when running in --shell mode. The usershell() function uses fixed-size stack buffers (command, arg, argv) without proper bounds checking on user input lines. Overly long inputs can overflow these buffers, corrupting stack memory. This can cause crashes or potentially allow arbitrary code execution in the context of the xmlcatalog process. The issue has been fixed in commit c2e233fc. The maintainers do not classify this as a vulnerability but as a bug.
Potential Impact
Exploitation can cause memory corruption leading to crashes or potentially arbitrary code execution within the xmlcatalog process. The CVSS 4.0 score is low (1.8), reflecting limited attack vector and complexity. There are no known exploits in the wild.
Mitigation Recommendations
A fix is available in the codebase as of commit c2e233fc. Users should update libxml2 to a version that includes this commit to remediate the issue. Since no official vendor advisory or patch release is provided, users should track the project repository for the fixed version. No additional mitigations are specified by the maintainers.
CVE-2026-11979: CWE-121: Stack-based Buffer Overflow in xmlsoft libxml2
Description
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.
CVSS v4.0
Score 1.8low
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The xmlcatalog utility in libxml2 is vulnerable to stack-based buffer overflows when running in --shell mode. The usershell() function uses fixed-size stack buffers (command, arg, argv) without proper bounds checking on user input lines. Overly long inputs can overflow these buffers, corrupting stack memory. This can cause crashes or potentially allow arbitrary code execution in the context of the xmlcatalog process. The issue has been fixed in commit c2e233fc. The maintainers do not classify this as a vulnerability but as a bug.
Potential Impact
Exploitation can cause memory corruption leading to crashes or potentially arbitrary code execution within the xmlcatalog process. The CVSS 4.0 score is low (1.8), reflecting limited attack vector and complexity. There are no known exploits in the wild.
Mitigation Recommendations
A fix is available in the codebase as of commit c2e233fc. Users should update libxml2 to a version that includes this commit to remediate the issue. Since no official vendor advisory or patch release is provided, users should track the project repository for the fixed version. No additional mitigations are specified by the maintainers.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CERT-PL
- Date Reserved
- 2026-06-11T13:20:24.839Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4274e727e9c79719eeb048
Added to database: 06/29/2026, 13:36:39 UTC
Last enriched: 06/29/2026, 13:52:21 UTC
Last updated: 06/29/2026, 22:29:30 UTC
Views: 47
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