CVE-2026-11979

Stack-Based Buffer Overflow in libxml2

Published Jun 29, 2026 CVSS 4.0 · 1.8 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Weaknesses CWE-120
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Xmlsoft
Xmlsoft libxml2
Vendors & Products Xmlsoft
Xmlsoft libxml2
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Stack-Based Buffer Overflow in libxml2
Weaknesses CWE-121
References
Metrics cvssV4_0

{'score': 1.8, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CERT-PL
Published
Updated
Jun 29, 2026, 1:59 PM
Reserved
Jun 11, 2026, 1:20 PM
Status
Analyzed
Published
Jun 29, 2026, 2:16 PM
Modified
Oct 25, 2026, 9:10 PM
Severity
Moderate
Public date
Jun 29, 2026, 1:21 PM