Stack-Based Buffer Overflow in xmlcatalog Utility of libxml2
CVE-2026-11979

1.8LOW

Key Information:

Vendor

Xmlsoft

Status
Libxml2
Vendor
CVE Published:
29 June 2026

What is CVE-2026-11979?

The xmlcatalog utility of libxml2 is vulnerable to multiple stack-based buffer overflows due to improper handling of user input in --shell mode. The usershell() function utilizes fixed-size stack buffers without adequate bounds checking, enabling attackers to craft overly long input lines that can overflow internal buffers. This memory corruption can lead to application crashes or allow the execution of arbitrary code within the xmlcatalog process. While the project maintainers regarded this issue as a bug, it is essential for users to recognize the potential security implications.

Affected Version(s)

libxml2 0 <= 2.15.3

References

https://cert.pl/en/posts/2026/06/CVE-2026-11979
third-party-advisory
https://gitlab.gnome.org/GNOME/libxml2/-/commit/c2e233fc1...
patch

CVSS V4

Score:
1.8
Severity:
LOW
Confidentiality:
None
Integrity:
None
Availability:
Low
Attack Vector:
Local
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Michał Majchrowicz (AFINE Team)
Marcin Wyczechowski (AFINE Team)
.