# CVE-2026-86140: In libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow. CVE-2026-86140 is fixed in 11 products on 1 platform, first by RHSA-2026:89759, released August 28, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-86140 - Priority: High - CVSS: 8.5 (Important) - EPSS: 0.0016 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 4, 2026 - Weakness: Stack-based Buffer Overflow - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-86140 ## Description In libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libxml2 Debian 14 | 2.15.4+dfsg-1 | [DEBIAN-CVE-2026-86140](https://patchblox.com/security/data/fix/linux/debian-cve-2026-86140.md) | Sep 11, 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_10.9 | [RHSA-2026:71641](https://patchblox.com/security/data/fix/linux/rhsa-2026-71641.md) | Sep 24, 2026 | | Linux | libxml2 RHEL 9 | 0:2.9.13-14.el9_8.5 | [RHSA-2026:71585](https://patchblox.com/security/data/fix/linux/rhsa-2026-71585.md) | Sep 25, 2026 | | Linux | libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm8 | [libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm8](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxml2-2.9.4-dfsg1-6.1ubuntu1.9-esm8.md) | Sep 22, 2026 | | Linux | libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm5 | [libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxml2-2.9.10-dfsg-5ubuntu0.20.04.10-esm5.md) | Sep 22, 2026 | | Linux | libxml2 Ubuntu 22.04.1 LTS (jammy) | 2.9.13+dfsg-1ubuntu0.13 | [libxml2 2.9.13+dfsg-1ubuntu0.13](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxml2-2.9.13-dfsg-1ubuntu0.13.md) | Sep 22, 2026 | | Linux | libxml2 Ubuntu 24.04.5 LTS (noble) | 2.9.14+dfsg-1.3ubuntu3.9 | [libxml2 2.9.14+dfsg-1.3ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxml2-2.9.14-dfsg-1.3ubuntu3.9.md) | Sep 22, 2026 | | Linux | libxml2 almalinux 10 | 2.12.5-10.el10_2.4 | [ALSA-2026:71586](https://patchblox.com/security/data/fix/linux/alsa-2026-71586.md) | Sep 24, 2026 | | Linux | libxml2 almalinux 8 | 2.9.7-21.el8_10.9 | [ALSA-2026:71641](https://patchblox.com/security/data/fix/linux/alsa-2026-71641.md) | Sep 24, 2026 | | Linux | libxml2 almalinux 9 | 2.9.13-14.el9_8.5 | [ALSA-2026:71585](https://patchblox.com/security/data/fix/linux/alsa-2026-71585.md) | Sep 24, 2026 | | Linux | libxml2 amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | | Linux | libxml2 ol 10 | 0:2.12.5-10.el10_2.4 | [ELSA-2026-71586](https://patchblox.com/security/data/fix/linux/elsa-2026-71586.md) | Sep 25, 2026 | | Linux | libxml2 ol 8 | 0:2.9.7-21.el8_10.9 | [ELSA-2026-71641](https://patchblox.com/security/data/fix/linux/elsa-2026-71641.md) | Sep 25, 2026 | | Linux | libxml2 ol 9 | 0:2.9.13-14.el9_8.5 | [ELSA-2026-71585](https://patchblox.com/security/data/fix/linux/elsa-2026-71585.md) | Sep 24, 2026 | | Linux | libxml2 rocky 10 | 0:2.12.5-10.el10_2.4 | [RLSA-2026:71586](https://patchblox.com/security/data/fix/linux/rlsa-2026-71586.md) | Sep 25, 2026 | | Linux | libxml2 rocky 8 | 0:2.9.7-21.el8_10.9 | [RLSA-2026:71641](https://patchblox.com/security/data/fix/linux/rlsa-2026-71641.md) | Sep 26, 2026 | | Linux | libxml2 rocky 9 | 0:2.9.13-14.el9_8.5 | [RLSA-2026:71585](https://patchblox.com/security/data/fix/linux/rlsa-2026-71585.md) | Sep 25, 2026 | | Linux | libxml2-16 Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.2 | [libxml2-16 2.15.2+dfsg-0.1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxml2-16-2.15.2-dfsg-0.1ubuntu0.2.md) | Sep 8, 2026 | | Linux | libxml2-debuginfo amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | | Linux | libxml2-debugsource amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | | Linux | libxml2-devel RHEL 8 | 0:2.9.7-21.el8_10.9 | [RHSA-2026:71641](https://patchblox.com/security/data/fix/linux/rhsa-2026-71641.md) | Sep 24, 2026 | | Linux | libxml2-devel RHEL 9 | 0:2.9.13-14.el9_8.5 | [RHSA-2026:71585](https://patchblox.com/security/data/fix/linux/rhsa-2026-71585.md) | Sep 25, 2026 | | Linux | libxml2-devel almalinux 10 | 2.12.5-10.el10_2.4 | [ALSA-2026:71586](https://patchblox.com/security/data/fix/linux/alsa-2026-71586.md) | Sep 24, 2026 | | Linux | libxml2-devel almalinux 8 | 2.9.7-21.el8_10.9 | [ALSA-2026:71641](https://patchblox.com/security/data/fix/linux/alsa-2026-71641.md) | Sep 24, 2026 | | Linux | libxml2-devel almalinux 9 | 2.9.13-14.el9_8.5 | [ALSA-2026:71585](https://patchblox.com/security/data/fix/linux/alsa-2026-71585.md) | Sep 24, 2026 | | Linux | libxml2-devel amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | | Linux | libxml2-devel ol 10 | 0:2.12.5-10.el10_2.4 | [ELSA-2026-71586](https://patchblox.com/security/data/fix/linux/elsa-2026-71586.md) | Sep 25, 2026 | | Linux | libxml2-devel ol 8 | 0:2.9.7-21.el8_10.9 | [ELSA-2026-71641](https://patchblox.com/security/data/fix/linux/elsa-2026-71641.md) | Sep 25, 2026 | | Linux | libxml2-devel ol 9 | 0:2.9.13-14.el9_8.5 | [ELSA-2026-71585](https://patchblox.com/security/data/fix/linux/elsa-2026-71585.md) | Sep 24, 2026 | | Linux | libxml2-source Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.2 | [libxml2-source 2.15.2+dfsg-0.1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxml2-source-2.15.2-dfsg-0.1ubuntu0.2.md) | Sep 8, 2026 | | Linux | libxml2-static almalinux 10 | 2.12.5-10.el10_2.4 | [ALSA-2026:71586](https://patchblox.com/security/data/fix/linux/alsa-2026-71586.md) | Sep 24, 2026 | | Linux | libxml2-static amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | | Linux | libxml2-static ol 10 | 0:2.12.5-10.el10_2.4 | [ELSA-2026-71586](https://patchblox.com/security/data/fix/linux/elsa-2026-71586.md) | Sep 25, 2026 | | Linux | libxml2-utils Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm8 | [libxml2-utils 2.9.4+dfsg1-6.1ubuntu1.9+esm8](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxml2-utils-2.9.4-dfsg1-6.1ubuntu1.9-esm8.md) | Sep 22, 2026 | | Linux | libxml2-utils Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm5 | [libxml2-utils 2.9.10+dfsg-5ubuntu0.20.04.10+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxml2-utils-2.9.10-dfsg-5ubuntu0.20.04.10-esm5.md) | Sep 22, 2026 | | Linux | libxml2-utils Ubuntu 22.04.1 LTS (jammy) | 2.9.13+dfsg-1ubuntu0.13 | [libxml2-utils 2.9.13+dfsg-1ubuntu0.13](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxml2-utils-2.9.13-dfsg-1ubuntu0.13.md) | Sep 22, 2026 | | Linux | libxml2-utils Ubuntu 24.04.5 LTS (noble) | 2.9.14+dfsg-1.3ubuntu3.9 | [libxml2-utils 2.9.14+dfsg-1.3ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxml2-utils-2.9.14-dfsg-1.3ubuntu3.9.md) | Sep 22, 2026 | | Linux | libxml2-utils Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.2 | [libxml2-utils 2.15.2+dfsg-0.1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxml2-utils-2.15.2-dfsg-0.1ubuntu0.2.md) | Sep 8, 2026 | | Linux | python-libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm8 | [python-libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm8](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-libxml2-2.9.4-dfsg1-6.1ubuntu1.9-esm8.md) | Sep 22, 2026 | | Linux | python-libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm5 | [python-libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python-libxml2-2.9.10-dfsg-5ubuntu0.20.04.10-esm5.md) | Sep 22, 2026 | | Linux | python3-libxml2 RHEL 8 | 0:2.9.7-21.el8_10.9 | [RHSA-2026:71641](https://patchblox.com/security/data/fix/linux/rhsa-2026-71641.md) | Sep 24, 2026 | | Linux | python3-libxml2 RHEL 9 | 0:2.9.13-14.el9_8.5 | [RHSA-2026:71585](https://patchblox.com/security/data/fix/linux/rhsa-2026-71585.md) | Sep 25, 2026 | | Linux | python3-libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm8 | [python3-libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm8](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-libxml2-2.9.4-dfsg1-6.1ubuntu1.9-esm8.md) | Sep 22, 2026 | | Linux | python3-libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm5 | [python3-libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-libxml2-2.9.10-dfsg-5ubuntu0.20.04.10-esm5.md) | Sep 22, 2026 | | Linux | python3-libxml2 Ubuntu 22.04.1 LTS (jammy) | 2.9.13+dfsg-1ubuntu0.13 | [python3-libxml2 2.9.13+dfsg-1ubuntu0.13](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-libxml2-2.9.13-dfsg-1ubuntu0.13.md) | Sep 22, 2026 | | Linux | python3-libxml2 Ubuntu 24.04.5 LTS (noble) | 2.9.14+dfsg-1.3ubuntu3.9 | [python3-libxml2 2.9.14+dfsg-1.3ubuntu3.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-libxml2-2.9.14-dfsg-1.3ubuntu3.9.md) | Sep 22, 2026 | | Linux | python3-libxml2 Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.2 | [python3-libxml2 2.15.2+dfsg-0.1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-libxml2-2.15.2-dfsg-0.1ubuntu0.2.md) | Sep 8, 2026 | | Linux | python3-libxml2 almalinux 10 | 2.12.5-10.el10_2.4 | [ALSA-2026:71586](https://patchblox.com/security/data/fix/linux/alsa-2026-71586.md) | Sep 24, 2026 | | Linux | python3-libxml2 almalinux 8 | 2.9.7-21.el8_10.9 | [ALSA-2026:71641](https://patchblox.com/security/data/fix/linux/alsa-2026-71641.md) | Sep 24, 2026 | | Linux | python3-libxml2 almalinux 9 | 2.9.13-14.el9_8.5 | [ALSA-2026:71585](https://patchblox.com/security/data/fix/linux/alsa-2026-71585.md) | Sep 24, 2026 | | Linux | python3-libxml2 amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | | Linux | python3-libxml2 ol 10 | 0:2.12.5-10.el10_2.4 | [ELSA-2026-71586](https://patchblox.com/security/data/fix/linux/elsa-2026-71586.md) | Sep 25, 2026 | | Linux | python3-libxml2 ol 8 | 0:2.9.7-21.el8_10.9 | [ELSA-2026-71641](https://patchblox.com/security/data/fix/linux/elsa-2026-71641.md) | Sep 25, 2026 | | Linux | python3-libxml2 ol 9 | 0:2.9.13-14.el9_8.5 | [ELSA-2026-71585](https://patchblox.com/security/data/fix/linux/elsa-2026-71585.md) | Sep 24, 2026 | | Linux | python3-libxml2-debuginfo amzn 2023 | 2.10.4-1.amzn2023.0.21 | [ALAS2023-2026-3122](https://patchblox.com/security/data/fix/linux/alas2023-2026-3122.md) | Sep 28, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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