# CVE-2026-25210: expat: In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is... CVE-2026-25210 is fixed in 11 products on 1 platform, first by expat 2.2.5-3ubuntu0.9+esm3, released January 29, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-25210 - Priority: High - CVSS: 7.8 (high) - EPSS: 0.0021 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jan 29, 2026 ## Description In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | expat Debian 12.15 (bookworm) | 2.5.0-1+deb12u4 | [DEBIAN-CVE-2026-25210](https://patchblox.com/security/data/fix/linux/debian-cve-2026-25210.md) | Jan 30, 2026 | | Linux | expat Debian 13.5 (trixie) | 2.8.2-1~deb13u1 | [DEBIAN-CVE-2026-25210](https://patchblox.com/security/data/fix/linux/debian-cve-2026-25210.md) | Jan 30, 2026 | | Linux | expat Debian 14 | 2.7.4-1 | [DEBIAN-CVE-2026-25210](https://patchblox.com/security/data/fix/linux/debian-cve-2026-25210.md) | Jan 30, 2026 | | Linux | expat Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.9+esm3 | [expat 2.2.5-3ubuntu0.9+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-expat-2.2.5-3ubuntu0.9-esm3.md) | Jan 29, 2026 | | Linux | expat Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.8+esm1 | [expat 2.2.9-1ubuntu0.8+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-expat-2.2.9-1ubuntu0.8-esm1.md) | Jan 29, 2026 | | Linux | expat Ubuntu 22.04.1 LTS (jammy) | 2.4.7-1ubuntu0.7 | [expat 2.4.7-1ubuntu0.7](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-expat-2.4.7-1ubuntu0.7.md) | Jan 29, 2026 | | Linux | expat Ubuntu 24.04.5 LTS (noble) | 2.6.1-2ubuntu0.4 | [expat 2.6.1-2ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-expat-2.6.1-2ubuntu0.4.md) | Jan 29, 2026 | | Linux | expat Ubuntu 25.10 (questing) | 2.7.1-2ubuntu0.2 | [expat 2.7.1-2ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-expat-2.7.1-2ubuntu0.2.md) | Jan 29, 2026 | | Linux | expat amzn 2023 | 2.6.3-1.amzn2023.0.4 | [ALAS2023-2026-1425](https://patchblox.com/security/data/fix/linux/alas2023-2026-1425.md) | Feb 16, 2026 | | Linux | expat opensuse-leap 15.6 | 2.7.1-150400.3.34.1 | [SUSE-SU-2026:0826-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0826-1.md) | Mar 5, 2026 | | Linux | expat opensuse-leap 16.0 | 2.7.1-160000.4.1 | [OPENSUSE-SU-2026:20306-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20306-1.md) | Mar 3, 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 | 2.7.1-160000.4.1 | [SUSE-SU-2026:20627-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20627-1.md) | Mar 3, 2026 | | Linux | expat-debuginfo amzn 2023 | 2.6.3-1.amzn2023.0.4 | [ALAS2023-2026-1425](https://patchblox.com/security/data/fix/linux/alas2023-2026-1425.md) | Feb 16, 2026 | | Linux | expat-debugsource amzn 2023 | 2.6.3-1.amzn2023.0.4 | [ALAS2023-2026-1425](https://patchblox.com/security/data/fix/linux/alas2023-2026-1425.md) | Feb 16, 2026 | | Linux | expat-devel amzn 2023 | 2.6.3-1.amzn2023.0.4 | [ALAS2023-2026-1425](https://patchblox.com/security/data/fix/linux/alas2023-2026-1425.md) | Feb 16, 2026 | | Linux | expat-static amzn 2023 | 2.6.3-1.amzn2023.0.4 | [ALAS2023-2026-1425](https://patchblox.com/security/data/fix/linux/alas2023-2026-1425.md) | Feb 16, 2026 | | Linux | firefox amzn 2023 | 140.7.0-1.amzn2023.0.2 | [ALAS2023-2026-1424](https://patchblox.com/security/data/fix/linux/alas2023-2026-1424.md) | Feb 16, 2026 | | Linux | firefox-debuginfo amzn 2023 | 140.7.0-1.amzn2023.0.2 | [ALAS2023-2026-1424](https://patchblox.com/security/data/fix/linux/alas2023-2026-1424.md) | Feb 16, 2026 | | Linux | firefox-debugsource amzn 2023 | 140.7.0-1.amzn2023.0.2 | [ALAS2023-2026-1424](https://patchblox.com/security/data/fix/linux/alas2023-2026-1424.md) | Feb 16, 2026 | | Linux | libexpat1 Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.9+esm3 | [libexpat1 2.2.5-3ubuntu0.9+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libexpat1-2.2.5-3ubuntu0.9-esm3.md) | Jan 29, 2026 | | Linux | libexpat1 Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.8+esm1 | [libexpat1 2.2.9-1ubuntu0.8+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libexpat1-2.2.9-1ubuntu0.8-esm1.md) | Jan 29, 2026 | | Linux | libexpat1 Ubuntu 22.04.1 LTS (jammy) | 2.4.7-1ubuntu0.7 | [libexpat1 2.4.7-1ubuntu0.7](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libexpat1-2.4.7-1ubuntu0.7.md) | Jan 29, 2026 | | Linux | libexpat1 Ubuntu 24.04.5 LTS (noble) | 2.6.1-2ubuntu0.4 | [libexpat1 2.6.1-2ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libexpat1-2.6.1-2ubuntu0.4.md) | Jan 29, 2026 | | Linux | libexpat1 Ubuntu 25.10 (questing) | 2.7.1-2ubuntu0.2 | [libexpat1 2.7.1-2ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libexpat1-2.7.1-2ubuntu0.2.md) | Jan 29, 2026 | | Linux | libxmltok1 Ubuntu 18.04.6 LTS (bionic) | 1.2-4ubuntu0.18.04.1~esm6 | [libxmltok1 1.2-4ubuntu0.18.04.1~esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxmltok1-1.2-4ubuntu0.18.04.1-esm6.md) | Jan 29, 2026 | | Linux | libxmltok1 Ubuntu 20.04 LTS (focal) | 1.2-4ubuntu0.20.04.1~esm6 | [libxmltok1 1.2-4ubuntu0.20.04.1~esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxmltok1-1.2-4ubuntu0.20.04.1-esm6.md) | Jan 29, 2026 | | Linux | libxmltok1 Ubuntu 22.04.1 LTS (jammy) | 1.2-4ubuntu0.22.04.1~esm6 | [libxmltok1 1.2-4ubuntu0.22.04.1~esm6](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxmltok1-1.2-4ubuntu0.22.04.1-esm6.md) | Jan 29, 2026 | | Linux | libxmltok1t64 Ubuntu 24.04.5 LTS (noble) | 1.2-4.1ubuntu2.24.0.4.1+esm4 | [libxmltok1t64 1.2-4.1ubuntu2.24.0.4.1+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxmltok1t64-1.2-4.1ubuntu2.24.0.4.1-esm4.md) | Jan 29, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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