# CVE-2026-88806: libX11 XkbGetMap Reply Heap-based Buffer Overflow CVE-2026-88806 is fixed in 11 products on 1 platform, first by RHSA-2026:95499, released September 21, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-88806 - Priority: High - CVSS: 7.5 (Important) - EPSS: 0.0020 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 21, 2026 - Weakness: Heap-based Buffer Overflow - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88806 ## Description A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libX11 RHEL 10 | 1.8.10-1.el10_0.1 | [RHSA-2026:95499](https://patchblox.com/security/data/fix/linux/rhsa-2026-95499.md) | Sep 21, 2026 | | Linux | libX11 RHEL 8 | 0:1.6.8-10.el8_10 | [RHSA-2026:89730](https://patchblox.com/security/data/fix/linux/rhsa-2026-89730.md) | Oct 27, 2026 | | Linux | libX11 RHEL 9 | 0:1.8.12-1.el9_8.1 | [RHSA-2026:91365](https://patchblox.com/security/data/fix/linux/rhsa-2026-91365.md) | Oct 30, 2026 | | Linux | libX11 almalinux 10 | 1.8.10-1.el10_2.1 | [ALSA-2026:91366](https://patchblox.com/security/data/fix/linux/alsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11 almalinux 8 | 1.6.8-10.el8_10 | [ALSA-2026:89730](https://patchblox.com/security/data/fix/linux/alsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11 almalinux 9 | 1.8.12-1.el9_8.1 | [ALSA-2026:91365](https://patchblox.com/security/data/fix/linux/alsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11 amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libX11 ol 10 | 0:1.8.10-1.el10_2.1 | [ELSA-2026-91366](https://patchblox.com/security/data/fix/linux/elsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11 ol 8 | 0:1.6.8-10.el8_10 | [ELSA-2026-89730](https://patchblox.com/security/data/fix/linux/elsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11 ol 9 | 0:1.8.12-1.el9_8.1 | [ELSA-2026-91365](https://patchblox.com/security/data/fix/linux/elsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11 opensuse-leap 16.0 | 1.8.10-160000.4.1 | [OPENSUSE-SU-2026:21908-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21908-1.md) | Sep 22, 2026 | | Linux | libX11 rocky 10 | 0:1.8.10-1.el10_2.1 | [RLSA-2026:91366](https://patchblox.com/security/data/fix/linux/rlsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11 rocky 8 | 0:1.6.8-10.el8_10 | [RLSA-2026:89730](https://patchblox.com/security/data/fix/linux/rlsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11 rocky 9 | 0:1.8.12-1.el9_8.1 | [RLSA-2026:91365](https://patchblox.com/security/data/fix/linux/rlsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11 sles 15.6 | 1.8.7-150600.3.11.1 | [SUSE-SU-2026:4501-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4501-1.md) | Oct 5, 2026 | | Linux | libX11 sles 15.7 | 1.8.10-150700.4.8.1 | [SUSE-SU-2026:4502-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4502-1.md) | Oct 5, 2026 | | Linux | libX11 sles 16.0 | 1.8.10-160000.4.1 | [SUSE-SU-2026:23899-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23899-1.md) | Sep 22, 2026 | | Linux | libX11-common RHEL 8 | 0:1.6.8-10.el8_10 | [RHSA-2026:89730](https://patchblox.com/security/data/fix/linux/rhsa-2026-89730.md) | Oct 27, 2026 | | Linux | libX11-common RHEL 9 | 0:1.8.12-1.el9_8.1 | [RHSA-2026:91365](https://patchblox.com/security/data/fix/linux/rhsa-2026-91365.md) | Oct 30, 2026 | | Linux | libX11-common almalinux 10 | 1.8.10-1.el10_2.1 | [ALSA-2026:91366](https://patchblox.com/security/data/fix/linux/alsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11-common almalinux 8 | 1.6.8-10.el8_10 | [ALSA-2026:89730](https://patchblox.com/security/data/fix/linux/alsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11-common almalinux 9 | 1.8.12-1.el9_8.1 | [ALSA-2026:91365](https://patchblox.com/security/data/fix/linux/alsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11-common amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libX11-common ol 10 | 0:1.8.10-1.el10_2.1 | [ELSA-2026-91366](https://patchblox.com/security/data/fix/linux/elsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11-common ol 8 | 0:1.6.8-10.el8_10 | [ELSA-2026-89730](https://patchblox.com/security/data/fix/linux/elsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11-common ol 9 | 0:1.8.12-1.el9_8.1 | [ELSA-2026-91365](https://patchblox.com/security/data/fix/linux/elsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11-debuginfo amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libX11-debugsource amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libX11-devel RHEL 8 | 0:1.6.8-10.el8_10 | [RHSA-2026:89730](https://patchblox.com/security/data/fix/linux/rhsa-2026-89730.md) | Oct 27, 2026 | | Linux | libX11-devel RHEL 9 | 0:1.8.12-1.el9_8.1 | [RHSA-2026:91365](https://patchblox.com/security/data/fix/linux/rhsa-2026-91365.md) | Oct 30, 2026 | | Linux | libX11-devel almalinux 10 | 1.8.10-1.el10_2.1 | [ALSA-2026:91366](https://patchblox.com/security/data/fix/linux/alsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11-devel almalinux 8 | 1.6.8-10.el8_10 | [ALSA-2026:89730](https://patchblox.com/security/data/fix/linux/alsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11-devel almalinux 9 | 1.8.12-1.el9_8.1 | [ALSA-2026:91365](https://patchblox.com/security/data/fix/linux/alsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11-devel amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libX11-devel ol 10 | 0:1.8.10-1.el10_2.1 | [ELSA-2026-91366](https://patchblox.com/security/data/fix/linux/elsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11-devel ol 8 | 0:1.6.8-10.el8_10 | [ELSA-2026-89730](https://patchblox.com/security/data/fix/linux/elsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11-devel ol 9 | 0:1.8.12-1.el9_8.1 | [ELSA-2026-91365](https://patchblox.com/security/data/fix/linux/elsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11-xcb RHEL 8 | 0:1.6.8-10.el8_10 | [RHSA-2026:89730](https://patchblox.com/security/data/fix/linux/rhsa-2026-89730.md) | Oct 27, 2026 | | Linux | libX11-xcb RHEL 9 | 0:1.8.12-1.el9_8.1 | [RHSA-2026:91365](https://patchblox.com/security/data/fix/linux/rhsa-2026-91365.md) | Oct 30, 2026 | | Linux | libX11-xcb almalinux 10 | 1.8.10-1.el10_2.1 | [ALSA-2026:91366](https://patchblox.com/security/data/fix/linux/alsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11-xcb almalinux 8 | 1.6.8-10.el8_10 | [ALSA-2026:89730](https://patchblox.com/security/data/fix/linux/alsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11-xcb almalinux 9 | 1.8.12-1.el9_8.1 | [ALSA-2026:91365](https://patchblox.com/security/data/fix/linux/alsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11-xcb amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libX11-xcb ol 10 | 0:1.8.10-1.el10_2.1 | [ELSA-2026-91366](https://patchblox.com/security/data/fix/linux/elsa-2026-91366.md) | Nov 7, 2026 | | Linux | libX11-xcb ol 8 | 0:1.6.8-10.el8_10 | [ELSA-2026-89730](https://patchblox.com/security/data/fix/linux/elsa-2026-89730.md) | Nov 7, 2026 | | Linux | libX11-xcb ol 9 | 0:1.8.12-1.el9_8.1 | [ELSA-2026-91365](https://patchblox.com/security/data/fix/linux/elsa-2026-91365.md) | Nov 7, 2026 | | Linux | libX11-xcb-debuginfo amzn 2023 | 1.8.10-2.amzn2023.0.2 | [ALAS2023-2026-3179](https://patchblox.com/security/data/fix/linux/alas2023-2026-3179.md) | Nov 7, 2026 | | Linux | libx11 Debian 14 | 2:1.8.14-1 | [DEBIAN-CVE-2026-88806](https://patchblox.com/security/data/fix/linux/debian-cve-2026-88806.md) | Sep 21, 2026 | | Linux | libx11-6 Ubuntu 18.04.6 LTS (bionic) | 2:1.6.4-3ubuntu0.4+esm3 | [libx11-6 2:1.6.4-3ubuntu0.4+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libx11-6-2-1.6.4-3ubuntu0.4-esm3.md) | Oct 13, 2026 | | Linux | libx11-6 Ubuntu 20.04 LTS (focal) | 2:1.6.9-2ubuntu1.6+esm1 | [libx11-6 2:1.6.9-2ubuntu1.6+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libx11-6-2-1.6.9-2ubuntu1.6-esm1.md) | Oct 13, 2026 | | Linux | libx11-6 Ubuntu 22.04.1 LTS (jammy) | 2:1.7.5-1ubuntu0.4 | [libx11-6 2:1.7.5-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libx11-6-2-1.7.5-1ubuntu0.4.md) | Oct 13, 2026 | | Linux | libx11-6 Ubuntu 24.04.5 LTS (noble) | 2:1.8.7-1ubuntu0.1 | [libx11-6 2:1.8.7-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libx11-6-2-1.8.7-1ubuntu0.1.md) | Oct 13, 2026 | | Linux | libx11-6 Ubuntu 26.04.1 LTS (resolute) | 2:1.8.13-1ubuntu0.1 | [libx11-6 2:1.8.13-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libx11-6-2-1.8.13-1ubuntu0.1.md) | Sep 28, 2026 | | Linux | libx11-data Ubuntu 18.04.6 LTS (bionic) | 2:1.6.4-3ubuntu0.4+esm3 | [libx11-data 2:1.6.4-3ubuntu0.4+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libx11-data-2-1.6.4-3ubuntu0.4-esm3.md) | Oct 13, 2026 | | Linux | libx11-data Ubuntu 20.04 LTS (focal) | 2:1.6.9-2ubuntu1.6+esm1 | [libx11-data 2:1.6.9-2ubuntu1.6+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libx11-data-2-1.6.9-2ubuntu1.6-esm1.md) | Oct 13, 2026 | | Linux | libx11-data Ubuntu 22.04.1 LTS (jammy) | 2:1.7.5-1ubuntu0.4 | [libx11-data 2:1.7.5-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libx11-data-2-1.7.5-1ubuntu0.4.md) | Oct 13, 2026 | | Linux | libx11-data Ubuntu 24.04.5 LTS (noble) | 2:1.8.7-1ubuntu0.1 | [libx11-data 2:1.8.7-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libx11-data-2-1.8.7-1ubuntu0.1.md) | Oct 13, 2026 | | Linux | libx11-data Ubuntu 26.04.1 LTS (resolute) | 2:1.8.13-1ubuntu0.1 | [libx11-data 2:1.8.13-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libx11-data-2-1.8.13-1ubuntu0.1.md) | Sep 28, 2026 | | Linux | libx11-xcb1 Ubuntu 18.04.6 LTS (bionic) | 2:1.6.4-3ubuntu0.4+esm3 | [libx11-xcb1 2:1.6.4-3ubuntu0.4+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libx11-xcb1-2-1.6.4-3ubuntu0.4-esm3.md) | Oct 13, 2026 | | Linux | libx11-xcb1 Ubuntu 20.04 LTS (focal) | 2:1.6.9-2ubuntu1.6+esm1 | [libx11-xcb1 2:1.6.9-2ubuntu1.6+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libx11-xcb1-2-1.6.9-2ubuntu1.6-esm1.md) | Oct 13, 2026 | | Linux | libx11-xcb1 Ubuntu 22.04.1 LTS (jammy) | 2:1.7.5-1ubuntu0.4 | [libx11-xcb1 2:1.7.5-1ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libx11-xcb1-2-1.7.5-1ubuntu0.4.md) | Oct 13, 2026 | | Linux | libx11-xcb1 Ubuntu 24.04.5 LTS (noble) | 2:1.8.7-1ubuntu0.1 | [libx11-xcb1 2:1.8.7-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libx11-xcb1-2-1.8.7-1ubuntu0.1.md) | Oct 13, 2026 | | Linux | libx11-xcb1 Ubuntu 26.04.1 LTS (resolute) | 2:1.8.13-1ubuntu0.1 | [libx11-xcb1 2:1.8.13-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libx11-xcb1-2-1.8.13-1ubuntu0.1.md) | Sep 28, 2026 | --- Data as of 2026-11-09T13:31:49Z UTC. 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