CVE-2026-11979 Stack-Based Buffer Overflow in libxml2
Stack-based buffer overflow in libxml2's xmlcatalog utility allows arbitrary code execution or crashes when processing long input in shell mode.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-11979?
CVE-2026-11979 is a low-severity memory corruption vulnerability in Xmlsoft Libxml2, published on 29 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
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.
Weakness: CWE-121
Which versions are affected by CVE-2026-11979?
It affects 1 product.
Linux distribution packages (40)
libxml2 AlmaLinux:10 | All versions | 2.12.5-10.el10_2.3 |
libxml2-devel AlmaLinux:10 | All versions | 2.12.5-10.el10_2.3 |
libxml2-static AlmaLinux:10 | All versions | 2.12.5-10.el10_2.3 |
python3-libxml2 AlmaLinux:10 | All versions | 2.12.5-10.el10_2.3 |
libxml2 AlmaLinux:8 | All versions | 2.9.7-21.el8_10.7 |
libxml2-devel AlmaLinux:8 | All versions | 2.9.7-21.el8_10.7 |
python3-libxml2 AlmaLinux:8 | All versions | 2.9.7-21.el8_10.7 |
libxml2 Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
libxml2-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
libxml2-debugsource Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
libxml2-devel Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
libxml2-static Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
python3-libxml2 Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
python3-libxml2-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 0:2.12.5-10.el10_2.3 |
libxml2-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.7-21.el8_10.7 |
libxml2-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.7-21.el8_10.7 |
libxml2-devel Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.7-21.el8_10.7 |
python3-libxml2-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.7-21.el8_10.7 |
libxml2 Red Hat:enterprise_linux:8::baseos | All versions | 0:2.9.7-21.el8_10.7 |
libxml2-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:2.9.7-21.el8_10.7 |
libxml2-debugsource Red Hat:enterprise_linux:8::baseos | All versions | 0:2.9.7-21.el8_10.7 |
python3-libxml2 Red Hat:enterprise_linux:8::baseos | All versions | 0:2.9.7-21.el8_10.7 |
python3-libxml2-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:2.9.7-21.el8_10.7 |
libxml2 Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.1.hum1 |
libxml2-16 Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.1.hum1 |
libxml2-devel Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.1.hum1 |
libxml2-static Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.1.hum1 |
python3-libxml2 Red Hat:hummingbird:1 | All versions | 0:2.15.3-0.1.1.hum1 |
libxml2 Rocky Linux:10 | All versions | 0:2.12.5-10.el10_2.3 |
libxml2 Rocky Linux:8 | All versions | 0:2.9.7-21.el8_10.7 |
libxml2 SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.9.14-150400.5.58.1 |
libxml2-python SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.9.14-150400.5.58.1 |
libxml2 SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 2.9.14-150400.5.58.1 |
libxml2-python SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 2.9.14-150400.5.58.1 |
libxml2 SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 2.10.3-150500.5.41.1 |
libxml2-python SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 2.10.3-150500.5.41.1 |
libxml2 SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 2.10.3-150500.5.41.1 |
libxml2-python SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 2.10.3-150500.5.41.1 |
libxml2 SUSE:Linux Enterprise Micro 5.3 | All versions | 2.9.14-150400.5.58.1 |
libxml2-python SUSE:Linux Enterprise Micro 5.3 | All versions | 2.9.14-150400.5.58.1 |
Products include Xmlsoft Libxml2.
How do I fix CVE-2026-11979?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-11979 being exploited?
There is no known exploitation of CVE-2026-11979 in the wild and no public exploit code.
Other vulnerabilities in Xmlsoft Libxml2
Sources
Also known as ALSA-2026:60394, ALSA-2026:61248, CLSA-2026-1782998484, CLSA-2026-1783006034, CLSA-2026-1783076182, CLSA-2026-1783076452 and 27 more.