# CVE-2026-11979: Stack-Based Buffer Overflow in libxml2 CVE-2026-11979 is fixed in 8 products on 1 platform, first by DEBIAN-CVE-2026-11979, released June 29, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-11979 - Priority: High - CVSS: 7.8 (Low) - EPSS: 0.0015 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 29, 2026 - Weakness: Stack-based Buffer Overflow - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-11979 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libxml2 Debian 14 | 2.15.4+dfsg-1 | [DEBIAN-CVE-2026-11979](https://patchblox.com/security/data/fix/linux/debian-cve-2026-11979.md) | Jun 29, 2026 | | Linux | libxml2 RHEL 10 | 2.12.5-9.el10_0.9 | [RHSA-2026:89759](https://patchblox.com/security/data/fix/linux/rhsa-2026-89759.md) | Aug 28, 2026 | | Linux | libxml2 RHEL 8 | 0:2.9.7-21.el8_10.7 | [RHSA-2026:61248](https://patchblox.com/security/data/fix/linux/rhsa-2026-61248.md) | Sep 13, 2026 | | Linux | libxml2 RHEL 9 | 0:2.9.13-14.el9_8.4 | [RHSA-2026:61247](https://patchblox.com/security/data/fix/linux/rhsa-2026-61247.md) | Sep 13, 2026 | | Linux | libxml2 almalinux 10 | 2.12.5-10.el10_2.3 | [ALSA-2026:60394](https://patchblox.com/security/data/fix/linux/alsa-2026-60394.md) | Aug 26, 2026 | | Linux | libxml2 almalinux 8 | 2.9.7-21.el8_10.7 | [ALSA-2026:61248](https://patchblox.com/security/data/fix/linux/alsa-2026-61248.md) | Aug 31, 2026 | | Linux | libxml2 almalinux 9 | 2.9.13-14.el9_8.4 | [ALSA-2026:61247](https://patchblox.com/security/data/fix/linux/alsa-2026-61247.md) | Aug 31, 2026 | | Linux | libxml2 amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | | Linux | libxml2 ol 10 | 0:2.12.5-10.el10_2.3 | [ELSA-2026-60394-0](https://patchblox.com/security/data/fix/linux/elsa-2026-60394-0.md) | Aug 27, 2026 | | Linux | libxml2 ol 8 | 0:2.9.7-21.el8_10.7 | [ELSA-2026-61248-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61248-0.md) | Sep 1, 2026 | | Linux | libxml2 ol 9 | 0:2.9.13-14.el9_8.4 | [ELSA-2026-61247-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61247-0.md) | Sep 1, 2026 | | Linux | libxml2 opensuse-leap 16.0 | 2.13.8-160000.5.1 | [OPENSUSE-SU-2026:21317-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21317-1.md) | Jul 13, 2026 | | Linux | libxml2 rocky 10 | 0:2.12.5-10.el10_2.3 | [RLSA-2026:60394](https://patchblox.com/security/data/fix/linux/rlsa-2026-60394.md) | Aug 28, 2026 | | Linux | libxml2 rocky 8 | 0:2.9.7-21.el8_10.7 | [RLSA-2026:61248](https://patchblox.com/security/data/fix/linux/rlsa-2026-61248.md) | Aug 31, 2026 | | Linux | libxml2 rocky 9 | 0:2.9.13-14.el9_8.4 | [RLSA-2026:61247](https://patchblox.com/security/data/fix/linux/rlsa-2026-61247.md) | Aug 31, 2026 | | Linux | libxml2 sles 15.6 | 2.10.3-150500.5.41.1 | [SUSE-SU-2026:3096-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3096-1.md) | Jul 17, 2026 | | Linux | libxml2 sles 15.7 | 2.12.10-150700.4.14.1 | [SUSE-SU-2026:3097-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3097-1.md) | Jul 17, 2026 | | Linux | libxml2 sles 16.0 | 2.13.8-160000.5.1 | [SUSE-SU-2026:22636-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22636-1.md) | Jul 13, 2026 | | Linux | libxml2-debuginfo amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | | Linux | libxml2-debugsource amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | | Linux | libxml2-devel RHEL 8 | 0:2.9.7-21.el8_10.7 | [RHSA-2026:61248](https://patchblox.com/security/data/fix/linux/rhsa-2026-61248.md) | Sep 13, 2026 | | Linux | libxml2-devel RHEL 9 | 0:2.9.13-14.el9_8.4 | [RHSA-2026:61247](https://patchblox.com/security/data/fix/linux/rhsa-2026-61247.md) | Sep 13, 2026 | | Linux | libxml2-devel almalinux 10 | 2.12.5-10.el10_2.3 | [ALSA-2026:60394](https://patchblox.com/security/data/fix/linux/alsa-2026-60394.md) | Aug 26, 2026 | | Linux | libxml2-devel almalinux 8 | 2.9.7-21.el8_10.7 | [ALSA-2026:61248](https://patchblox.com/security/data/fix/linux/alsa-2026-61248.md) | Aug 31, 2026 | | Linux | libxml2-devel almalinux 9 | 2.9.13-14.el9_8.4 | [ALSA-2026:61247](https://patchblox.com/security/data/fix/linux/alsa-2026-61247.md) | Aug 31, 2026 | | Linux | libxml2-devel amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | | Linux | libxml2-devel ol 10 | 0:2.12.5-10.el10_2.3 | [ELSA-2026-60394-0](https://patchblox.com/security/data/fix/linux/elsa-2026-60394-0.md) | Aug 27, 2026 | | Linux | libxml2-devel ol 8 | 0:2.9.7-21.el8_10.7 | [ELSA-2026-61248-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61248-0.md) | Sep 1, 2026 | | Linux | libxml2-devel ol 9 | 0:2.9.13-14.el9_8.4 | [ELSA-2026-61247-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61247-0.md) | Sep 1, 2026 | | Linux | libxml2-python opensuse-leap 16.0 | 2.13.8-160000.5.1 | [OPENSUSE-SU-2026:21317-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21317-1.md) | Jul 13, 2026 | | Linux | libxml2-python sles 15.6 | 2.10.3-150500.5.41.1 | [SUSE-SU-2026:3096-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3096-1.md) | Jul 17, 2026 | | Linux | libxml2-python sles 15.7 | 2.12.10-150700.4.14.1 | [SUSE-SU-2026:3097-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3097-1.md) | Jul 17, 2026 | | Linux | libxml2-python sles 16.0 | 2.13.8-160000.5.1 | [SUSE-SU-2026:22636-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22636-1.md) | Jul 13, 2026 | | Linux | libxml2-static almalinux 10 | 2.12.5-10.el10_2.3 | [ALSA-2026:60394](https://patchblox.com/security/data/fix/linux/alsa-2026-60394.md) | Aug 26, 2026 | | Linux | libxml2-static amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | | Linux | libxml2-static ol 10 | 0:2.12.5-10.el10_2.3 | [ELSA-2026-60394-0](https://patchblox.com/security/data/fix/linux/elsa-2026-60394-0.md) | Aug 27, 2026 | | Linux | python3-libxml2 RHEL 8 | 0:2.9.7-21.el8_10.7 | [RHSA-2026:61248](https://patchblox.com/security/data/fix/linux/rhsa-2026-61248.md) | Sep 13, 2026 | | Linux | python3-libxml2 RHEL 9 | 0:2.9.13-14.el9_8.4 | [RHSA-2026:61247](https://patchblox.com/security/data/fix/linux/rhsa-2026-61247.md) | Sep 13, 2026 | | Linux | python3-libxml2 almalinux 10 | 2.12.5-10.el10_2.3 | [ALSA-2026:60394](https://patchblox.com/security/data/fix/linux/alsa-2026-60394.md) | Aug 26, 2026 | | Linux | python3-libxml2 almalinux 8 | 2.9.7-21.el8_10.7 | [ALSA-2026:61248](https://patchblox.com/security/data/fix/linux/alsa-2026-61248.md) | Aug 31, 2026 | | Linux | python3-libxml2 almalinux 9 | 2.9.13-14.el9_8.4 | [ALSA-2026:61247](https://patchblox.com/security/data/fix/linux/alsa-2026-61247.md) | Aug 31, 2026 | | Linux | python3-libxml2 amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | | Linux | python3-libxml2 ol 10 | 0:2.12.5-10.el10_2.3 | [ELSA-2026-60394-0](https://patchblox.com/security/data/fix/linux/elsa-2026-60394-0.md) | Aug 27, 2026 | | Linux | python3-libxml2 ol 8 | 0:2.9.7-21.el8_10.7 | [ELSA-2026-61248-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61248-0.md) | Sep 1, 2026 | | Linux | python3-libxml2 ol 9 | 0:2.9.13-14.el9_8.4 | [ELSA-2026-61247-0](https://patchblox.com/security/data/fix/linux/elsa-2026-61247-0.md) | Sep 1, 2026 | | Linux | python3-libxml2-debuginfo amzn 2023 | 2.10.4-1.amzn2023.0.20 | [ALAS2023-2026-1992](https://patchblox.com/security/data/fix/linux/alas2023-2026-1992.md) | Jul 20, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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