# CVE-2026-56405: libexpat before 2.8.2 has an integer overflow in getAttributeId. CVE-2026-56405 is fixed in 13 products on 1 platform, first by libxmltok1 1.2-4ubuntu0.18.04.1~esm7, released June 21, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-56405 - Priority: Routine - CVSS: 6.9 (Moderate) - EPSS: 0.0013 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 21, 2026 - Weakness: Integer Overflow or Wraparound - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56405 ## Description libexpat before 2.8.2 has an integer overflow in getAttributeId. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | MozillaFirefox opensuse-leap 16.0 | 153.5.0-160000.1.1 | [OPENSUSE-SU-2026:22139-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22139-1.md) | Nov 7, 2026 | | Linux | MozillaFirefox sles 15.6 | 153.5.0-150400.157.16.1 | [SUSE-SU-2026:4834-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4834-1.md) | Nov 7, 2026 | | Linux | MozillaFirefox sles 15.7 | 153.5.0-150400.157.16.1 | [SUSE-SU-2026:4834-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4834-1.md) | Nov 7, 2026 | | Linux | MozillaFirefox sles 16.0 | 153.5.0-160000.1.1 | [SUSE-SU-2026:24260-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24260-1.md) | Nov 7, 2026 | | Linux | MozillaThunderbird sles 15.7 | 153.5.0-150400.13.9.1 | [SUSE-SU-2026:4736-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4736-1.md) | Nov 7, 2026 | | Linux | expat Debian 12.15 (bookworm) | 2.5.0-1+deb12u3 | [DEBIAN-CVE-2026-56405](https://patchblox.com/security/data/fix/linux/debian-cve-2026-56405.md) | Jun 28, 2026 | | Linux | expat Debian 13.5 (trixie) | 2.8.2-1~deb13u1 | [DEBIAN-CVE-2026-56405](https://patchblox.com/security/data/fix/linux/debian-cve-2026-56405.md) | Jun 28, 2026 | | Linux | expat Debian 14 | 2.8.2-1 | [DEBIAN-CVE-2026-56405](https://patchblox.com/security/data/fix/linux/debian-cve-2026-56405.md) | Jun 28, 2026 | | Linux | expat Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.9+esm4 | [expat 2.2.5-3ubuntu0.9+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-expat-2.2.5-3ubuntu0.9-esm4.md) | Jun 21, 2026 | | Linux | expat Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.8+esm2 | [expat 2.2.9-1ubuntu0.8+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-expat-2.2.9-1ubuntu0.8-esm2.md) | Jun 21, 2026 | | Linux | expat Ubuntu 22.04.1 LTS (jammy) | 2.4.7-1ubuntu0.8 | [expat 2.4.7-1ubuntu0.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-expat-2.4.7-1ubuntu0.8.md) | Jun 21, 2026 | | Linux | expat Ubuntu 24.04.5 LTS (noble) | 2.6.1-2ubuntu0.5 | [expat 2.6.1-2ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-expat-2.6.1-2ubuntu0.5.md) | Jun 21, 2026 | | Linux | expat Ubuntu 26.04.1 LTS (resolute) | 2.7.4-1ubuntu0.1 | [expat 2.7.4-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-expat-2.7.4-1ubuntu0.1.md) | Jun 21, 2026 | | Linux | expat amzn 2023 | 2.8.3-1.amzn2023.0.1 | [ALAS2023-2026-2157](https://patchblox.com/security/data/fix/linux/alas2023-2026-2157.md) | Sep 14, 2026 | | Linux | expat opensuse-leap 16.0 | 2.8.5-160000.1.1 | [OPENSUSE-SU-2026:22177-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22177-1.md) | Nov 7, 2026 | | Linux | expat sles 15.6 | 2.8.5-150400.3.40.1 | [SUSE-SU-2026:4623-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4623-1.md) | Nov 7, 2026 | | Linux | expat sles 15.7 | 2.8.5-150700.3.15.1 | [SUSE-SU-2026:4619-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4619-1.md) | Nov 7, 2026 | | Linux | expat sles 16.0 | 2.8.5-160000.1.1 | [SUSE-SU-2026:24469-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24469-1.md) | Nov 7, 2026 | | Linux | expat-debuginfo amzn 2023 | 2.8.3-1.amzn2023.0.1 | [ALAS2023-2026-2157](https://patchblox.com/security/data/fix/linux/alas2023-2026-2157.md) | Sep 14, 2026 | | Linux | expat-debugsource amzn 2023 | 2.8.3-1.amzn2023.0.1 | [ALAS2023-2026-2157](https://patchblox.com/security/data/fix/linux/alas2023-2026-2157.md) | Sep 14, 2026 | | Linux | expat-devel amzn 2023 | 2.8.3-1.amzn2023.0.1 | [ALAS2023-2026-2157](https://patchblox.com/security/data/fix/linux/alas2023-2026-2157.md) | Sep 14, 2026 | | Linux | expat-static amzn 2023 | 2.8.3-1.amzn2023.0.1 | [ALAS2023-2026-2157](https://patchblox.com/security/data/fix/linux/alas2023-2026-2157.md) | Sep 14, 2026 | | Linux | firefox amzn 2023 | 140.12.0-1.amzn2023.0.1 | [ALAS2023-2026-1928](https://patchblox.com/security/data/fix/linux/alas2023-2026-1928.md) | Jul 6, 2026 | | Linux | firefox-debuginfo amzn 2023 | 140.12.0-1.amzn2023.0.1 | [ALAS2023-2026-1928](https://patchblox.com/security/data/fix/linux/alas2023-2026-1928.md) | Jul 6, 2026 | | Linux | firefox-debugsource amzn 2023 | 140.12.0-1.amzn2023.0.1 | [ALAS2023-2026-1928](https://patchblox.com/security/data/fix/linux/alas2023-2026-1928.md) | Jul 6, 2026 | | Linux | libexpat1 Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.9+esm4 | [libexpat1 2.2.5-3ubuntu0.9+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libexpat1-2.2.5-3ubuntu0.9-esm4.md) | Jun 21, 2026 | | Linux | libexpat1 Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.8+esm2 | [libexpat1 2.2.9-1ubuntu0.8+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libexpat1-2.2.9-1ubuntu0.8-esm2.md) | Jun 21, 2026 | | Linux | libexpat1 Ubuntu 22.04.1 LTS (jammy) | 2.4.7-1ubuntu0.8 | [libexpat1 2.4.7-1ubuntu0.8](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libexpat1-2.4.7-1ubuntu0.8.md) | Jun 21, 2026 | | Linux | libexpat1 Ubuntu 24.04.5 LTS (noble) | 2.6.1-2ubuntu0.5 | [libexpat1 2.6.1-2ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libexpat1-2.6.1-2ubuntu0.5.md) | Jun 21, 2026 | | Linux | libexpat1 Ubuntu 26.04.1 LTS (resolute) | 2.7.4-1ubuntu0.1 | [libexpat1 2.7.4-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libexpat1-2.7.4-1ubuntu0.1.md) | Jun 21, 2026 | | Linux | libxmltok1 Ubuntu 18.04.6 LTS (bionic) | 1.2-4ubuntu0.18.04.1~esm7 | [libxmltok1 1.2-4ubuntu0.18.04.1~esm7](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxmltok1-1.2-4ubuntu0.18.04.1-esm7.md) | Jun 21, 2026 | | Linux | libxmltok1 Ubuntu 20.04 LTS (focal) | 1.2-4ubuntu0.20.04.1~esm7 | [libxmltok1 1.2-4ubuntu0.20.04.1~esm7](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxmltok1-1.2-4ubuntu0.20.04.1-esm7.md) | Jun 21, 2026 | | Linux | libxmltok1 Ubuntu 22.04.1 LTS (jammy) | 1.2-4ubuntu0.22.04.1~esm7 | [libxmltok1 1.2-4ubuntu0.22.04.1~esm7](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxmltok1-1.2-4ubuntu0.22.04.1-esm7.md) | Jun 21, 2026 | | Linux | libxmltok1t64 Ubuntu 24.04.5 LTS (noble) | 1.2-4.1ubuntu2.24.0.4.1+esm5 | [libxmltok1t64 1.2-4.1ubuntu2.24.0.4.1+esm5](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxmltok1t64-1.2-4.1ubuntu2.24.0.4.1-esm5.md) | Jun 21, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.