# CVE-2026-76781: libxml2: A flaw was found in libxml2

CVE-2026-76781 is fixed in 11 products on 1 platform, first by libxml2-16 2.15.2+dfsg-0.1ubuntu0.3, released September 17, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-76781
- Priority: Routine
- CVSS: 5.5 (Medium)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026

## Description

A flaw was found in libxml2. A local user or an attacker providing a specially crafted XML catalog can trigger a NULL pointer dereference during XML catalog parsing. This occurs when a `nextCatalog` element lacks its mandatory `catalog` attribute, leading to the application crashing and causing a Denial of Service (DoS).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libxml2 Debian 14 | 2.15.4+dfsg-1 | [DEBIAN-CVE-2026-76781](https://patchblox.com/security/data/fix/linux/debian-cve-2026-76781.md) | Sep 20, 2026 |
| Linux | libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm9 | [libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxml2-2.9.4-dfsg1-6.1ubuntu1.9-esm9.md) | Oct 9, 2026 |
| Linux | libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm6 | [libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxml2-2.9.10-dfsg-5ubuntu0.20.04.10-esm6.md) | Oct 9, 2026 |
| Linux | libxml2 Ubuntu 22.04.1 LTS (jammy) | 2.9.13+dfsg-1ubuntu0.14 | [libxml2 2.9.13+dfsg-1ubuntu0.14](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxml2-2.9.13-dfsg-1ubuntu0.14.md) | Oct 9, 2026 |
| Linux | libxml2 Ubuntu 24.04.5 LTS (noble) | 2.9.14+dfsg-1.3ubuntu3.10 | [libxml2 2.9.14+dfsg-1.3ubuntu3.10](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxml2-2.9.14-dfsg-1.3ubuntu3.10.md) | Oct 9, 2026 |
| Linux | libxml2 amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |
| Linux | libxml2-16 Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.3 | [libxml2-16 2.15.2+dfsg-0.1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxml2-16-2.15.2-dfsg-0.1ubuntu0.3.md) | Sep 17, 2026 |
| Linux | libxml2-debuginfo amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |
| Linux | libxml2-debugsource amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |
| Linux | libxml2-devel amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |
| Linux | libxml2-source Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.3 | [libxml2-source 2.15.2+dfsg-0.1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxml2-source-2.15.2-dfsg-0.1ubuntu0.3.md) | Sep 17, 2026 |
| Linux | libxml2-static amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |
| Linux | libxml2-utils Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm9 | [libxml2-utils 2.9.4+dfsg1-6.1ubuntu1.9+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxml2-utils-2.9.4-dfsg1-6.1ubuntu1.9-esm9.md) | Oct 9, 2026 |
| Linux | libxml2-utils Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm6 | [libxml2-utils 2.9.10+dfsg-5ubuntu0.20.04.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxml2-utils-2.9.10-dfsg-5ubuntu0.20.04.10-esm6.md) | Oct 9, 2026 |
| Linux | libxml2-utils Ubuntu 22.04.1 LTS (jammy) | 2.9.13+dfsg-1ubuntu0.14 | [libxml2-utils 2.9.13+dfsg-1ubuntu0.14](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxml2-utils-2.9.13-dfsg-1ubuntu0.14.md) | Oct 9, 2026 |
| Linux | libxml2-utils Ubuntu 24.04.5 LTS (noble) | 2.9.14+dfsg-1.3ubuntu3.10 | [libxml2-utils 2.9.14+dfsg-1.3ubuntu3.10](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxml2-utils-2.9.14-dfsg-1.3ubuntu3.10.md) | Oct 9, 2026 |
| Linux | libxml2-utils Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.3 | [libxml2-utils 2.15.2+dfsg-0.1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxml2-utils-2.15.2-dfsg-0.1ubuntu0.3.md) | Sep 17, 2026 |
| Linux | python-libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm9 | [python-libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-libxml2-2.9.4-dfsg1-6.1ubuntu1.9-esm9.md) | Oct 9, 2026 |
| Linux | python-libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm6 | [python-libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python-libxml2-2.9.10-dfsg-5ubuntu0.20.04.10-esm6.md) | Oct 9, 2026 |
| Linux | python3-libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.9+esm9 | [python3-libxml2 2.9.4+dfsg1-6.1ubuntu1.9+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-libxml2-2.9.4-dfsg1-6.1ubuntu1.9-esm9.md) | Oct 9, 2026 |
| Linux | python3-libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.10+esm6 | [python3-libxml2 2.9.10+dfsg-5ubuntu0.20.04.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-libxml2-2.9.10-dfsg-5ubuntu0.20.04.10-esm6.md) | Oct 9, 2026 |
| Linux | python3-libxml2 Ubuntu 22.04.1 LTS (jammy) | 2.9.13+dfsg-1ubuntu0.14 | [python3-libxml2 2.9.13+dfsg-1ubuntu0.14](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-libxml2-2.9.13-dfsg-1ubuntu0.14.md) | Oct 9, 2026 |
| Linux | python3-libxml2 Ubuntu 24.04.5 LTS (noble) | 2.9.14+dfsg-1.3ubuntu3.10 | [python3-libxml2 2.9.14+dfsg-1.3ubuntu3.10](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-libxml2-2.9.14-dfsg-1.3ubuntu3.10.md) | Oct 9, 2026 |
| Linux | python3-libxml2 Ubuntu 26.04.1 LTS (resolute) | 2.15.2+dfsg-0.1ubuntu0.3 | [python3-libxml2 2.15.2+dfsg-0.1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-libxml2-2.15.2-dfsg-0.1ubuntu0.3.md) | Sep 17, 2026 |
| Linux | python3-libxml2 amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |
| Linux | python3-libxml2-debuginfo amzn 2023 | 2.10.4-1.amzn2023.0.22 | [ALAS2023-2026-3341](https://patchblox.com/security/data/fix/linux/alas2023-2026-3341.md) | Nov 7, 2026 |

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Data as of 2026-11-09T07:25:28Z 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

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