Vulnerability · Published Jun 29, 2026 · Assigned by CERT-PL
CVE-2026-11979Stack-Based Buffer Overflow in libxml2
Low 1.8
In plain English
A low-severity stack buffer overflow in libxml2 from xmlsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | libxml2 | 2.12.5-10.el10_2.3 | ALSA-2026:60394 |
| AlmaLinux:8 | libxml2 | 2.9.7-21.el8_10.7 | ALSA-2026:61248 |
| AlmaLinux:9 | libxml2 | 2.9.13-14.el9_8.4 | ALSA-2026:61247 |
| AlmaLinux:10 | libxml2-devel | 2.12.5-10.el10_2.3 | ALSA-2026:60394 |
| AlmaLinux:8 | libxml2-devel | 2.9.7-21.el8_10.7 | ALSA-2026:61248 |
| AlmaLinux:9 | libxml2-devel | 2.9.13-14.el9_8.4 | ALSA-2026:61247 |
| AlmaLinux:10 | libxml2-static | 2.12.5-10.el10_2.3 | ALSA-2026:60394 |
| AlmaLinux:10 | python3-libxml2 | 2.12.5-10.el10_2.3 | ALSA-2026:60394 |
| AlmaLinux:8 | python3-libxml2 | 2.9.7-21.el8_10.7 | ALSA-2026:61248 |
| AlmaLinux:9 | python3-libxml2 | 2.9.13-14.el9_8.4 | ALSA-2026:61247 |
| Debian:12 | libxml2 | no fix listed | DEBIAN-CVE-2026-11979 |
| Debian:13 | libxml2 | no fix listed | DEBIAN-CVE-2026-11979 |
| Debian:14 | libxml2 | 2.15.4+dfsg-1 | DEBIAN-CVE-2026-11979 |
| Rocky Linux:10 | libxml2 | 0:2.12.5-10.el10_2.3 | RLSA-2026:60394 |
| Rocky Linux:8 | libxml2 | 0:2.9.7-21.el8_10.7 | RLSA-2026:61248 |
| Rocky Linux:9 | libxml2 | 0:2.9.13-14.el9_8.4 | RLSA-2026:61247 |
| Ubuntu:22.04:LTS | libxml2 | no fix listed | UBUNTU-CVE-2026-11979 |
| Ubuntu:24.04:LTS | libxml2 | no fix listed | UBUNTU-CVE-2026-11979 |
| Ubuntu:25.10 | libxml2 | no fix listed | UBUNTU-CVE-2026-11979 |
| Ubuntu:26.04:LTS | libxml2 | no fix listed | UBUNTU-CVE-2026-11979 |
Affected products (as reported)
Weakness: CWE-121 · 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