# CVE-2021-45960: expat: In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) placesin the storeAtts function in xmlparse.c can... CVE-2021-45960 is fixed in 9 products on 1 platform, first by DEBIAN-CVE-2021-45960, released January 1, 2022. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2021-45960 - Priority: High - CVSS: 9.8 (Low) - EPSS: 0.0467 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jan 1, 2022 ## Description In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) placesin the storeAtts function in xmlparse.c can lead to realloc misbehavior(e.g., allocating too few bytes, or only freeing memory). ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | expat Debian 11.6 (bullseye) | 2.2.10-2+deb11u1 | [DSA-5073-1](https://patchblox.com/security/data/fix/linux/dsa-5073-1.md) | Feb 12, 2022 | | Linux | expat Debian 12.15 (bookworm) | 2.4.3-1 | [DEBIAN-CVE-2021-45960](https://patchblox.com/security/data/fix/linux/debian-cve-2021-45960.md) | Jan 1, 2022 | | Linux | expat Debian 13.5 (trixie) | 2.4.3-1 | [DEBIAN-CVE-2021-45960](https://patchblox.com/security/data/fix/linux/debian-cve-2021-45960.md) | Jan 1, 2022 | | Linux | expat Debian 14 | 2.4.3-1 | [DEBIAN-CVE-2021-45960](https://patchblox.com/security/data/fix/linux/debian-cve-2021-45960.md) | Jan 1, 2022 | | Linux | expat RHEL 8 | 0:2.2.5-4.el8_5.3 | [RHSA-2022:0951](https://patchblox.com/security/data/fix/linux/rhsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.4 | [expat 2.2.5-3ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-expat-2.2.5-3ubuntu0.4.md) | Feb 14, 2022 | | Linux | expat Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.2 | [expat 2.2.9-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-expat-2.2.9-1ubuntu0.2.md) | Feb 14, 2022 | | Linux | expat Ubuntu 22.04.1 LTS (jammy) | 2.4.3-1 | [expat 2.4.3-1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-expat-2.4.3-1.md) | Jan 10, 2022 | | Linux | expat Ubuntu 24.10 (oracular) | 2.4.3-1 | [expat 2.4.3-1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-expat-2.4.3-1.md) | Jan 16, 2026 | | Linux | expat Ubuntu 25.04 (plucky) | 2.4.3-1 | [expat 2.4.3-1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-expat-2.4.3-1.md) | Jan 16, 2026 | | Linux | expat almalinux 8 | 2.2.5-8.el8_6.2 | [ALSA-2022:0951](https://patchblox.com/security/data/fix/linux/alsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat amzn 2023 | 2.5.0-1.amzn2023.0.2 | [ALAS2023-2023-058](https://patchblox.com/security/data/fix/linux/alas2023-2023-058.md) | Feb 17, 2023 | | Linux | expat ol 8 | 0:2.2.5-4.el8_5.3 | [ELSA-2022-0951](https://patchblox.com/security/data/fix/linux/elsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat rocky 8 | 0:2.2.5-4.el8_5.3 | [RLSA-2022:0951](https://patchblox.com/security/data/fix/linux/rlsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat-debuginfo amzn 2023 | 2.5.0-1.amzn2023.0.2 | [ALAS2023-2023-058](https://patchblox.com/security/data/fix/linux/alas2023-2023-058.md) | Feb 17, 2023 | | Linux | expat-debugsource amzn 2023 | 2.5.0-1.amzn2023.0.2 | [ALAS2023-2023-058](https://patchblox.com/security/data/fix/linux/alas2023-2023-058.md) | Feb 17, 2023 | | Linux | expat-devel RHEL 8 | 0:2.2.5-4.el8_5.3 | [RHSA-2022:0951](https://patchblox.com/security/data/fix/linux/rhsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat-devel almalinux 8 | 2.2.5-8.el8_6.2 | [ALSA-2022:0951](https://patchblox.com/security/data/fix/linux/alsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat-devel amzn 2023 | 2.5.0-1.amzn2023.0.2 | [ALAS2023-2023-058](https://patchblox.com/security/data/fix/linux/alas2023-2023-058.md) | Feb 17, 2023 | | Linux | expat-devel ol 8 | 0:2.2.5-4.el8_5.3 | [ELSA-2022-0951](https://patchblox.com/security/data/fix/linux/elsa-2022-0951.md) | Mar 16, 2022 | | Linux | expat-static amzn 2023 | 2.5.0-1.amzn2023.0.2 | [ALAS2023-2023-058](https://patchblox.com/security/data/fix/linux/alas2023-2023-058.md) | Feb 17, 2023 | | Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 98.0+build3-0ubuntu0.18.04.2 | [firefox 98.0+build3-0ubuntu0.18.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-98.0-build3-0ubuntu0.18.04.2.md) | Mar 8, 2022 | | Linux | firefox Ubuntu 20.04 LTS (focal) | 98.0+build3-0ubuntu0.20.04.2 | [firefox 98.0+build3-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-98.0-build3-0ubuntu0.20.04.2.md) | Mar 8, 2022 | | Linux | firefox Ubuntu 22.04.1 LTS (jammy) | 1:1snap1-0ubuntu1 | [firefox 1:1snap1-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-firefox-1-1snap1-0ubuntu1.md) | Apr 6, 2022 | | Linux | firefox Ubuntu 24.10 (oracular) | 1:1snap1-0ubuntu1 | [firefox 1:1snap1-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-firefox-1-1snap1-0ubuntu1.md) | Feb 15, 2022 | | Linux | firefox Ubuntu 25.04 (plucky) | 1:1snap1-0ubuntu1 | [firefox 1:1snap1-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-firefox-1-1snap1-0ubuntu1.md) | Feb 15, 2022 | | Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 98.0+build3-0ubuntu0.18.04.2 | [firefox-geckodriver 98.0+build3-0ubuntu0.18.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-98.0-build3-0ubuntu0.18.04.2.md) | Mar 8, 2022 | | Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 98.0+build3-0ubuntu0.20.04.2 | [firefox-geckodriver 98.0+build3-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-98.0-build3-0ubuntu0.20.04.2.md) | Mar 8, 2022 | | Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 98.0+build3-0ubuntu0.18.04.2 | [firefox-mozsymbols 98.0+build3-0ubuntu0.18.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-98.0-build3-0ubuntu0.18.04.2.md) | Mar 8, 2022 | | Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 98.0+build3-0ubuntu0.20.04.2 | [firefox-mozsymbols 98.0+build3-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-98.0-build3-0ubuntu0.20.04.2.md) | Mar 8, 2022 | | Linux | libexpat1 Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.4 | [libexpat1 2.2.5-3ubuntu0.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libexpat1-2.2.5-3ubuntu0.4.md) | Feb 14, 2022 | | Linux | libexpat1 Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.2 | [libexpat1 2.2.9-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libexpat1-2.2.9-1ubuntu0.2.md) | Feb 14, 2022 | | Linux | libexpat1 Ubuntu 22.04.1 LTS (jammy) | 2.4.3-1 | [libexpat1 2.4.3-1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libexpat1-2.4.3-1.md) | Jan 10, 2022 | | Linux | libexpat1 Ubuntu 24.10 (oracular) | 2.4.3-1 | [libexpat1 2.4.3-1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-libexpat1-2.4.3-1.md) | Jan 16, 2026 | | Linux | libexpat1 Ubuntu 25.04 (plucky) | 2.4.3-1 | [libexpat1 2.4.3-1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libexpat1-2.4.3-1.md) | Jan 16, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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