# CVE-2026-4271: libsoup3: A flaw was found in libsoup, a library for handling HTTP requests CVE-2026-4271 is fixed in 8 products on 1 platform, first by RHSA-2026:17482, released March 30, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-4271 - Priority: Routine - CVSS: 5.9 (moderate) - EPSS: 0.0088 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 16, 2026 ## Description A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the application attempting to access memory that has already been freed, potentially causing application instability or crashes, resulting in a Denial of Service (DoS). ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | gir1.2-soup-3.0 Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | [gir1.2-soup-3.0 3.4.4-5ubuntu0.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-gir1.2-soup-3.0-3.4.4-5ubuntu0.9.md) | Sep 4, 2026 | | Linux | gir1.2-soup-3.0 Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | [gir1.2-soup-3.0 3.6.6-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-gir1.2-soup-3.0-3.6.6-1ubuntu0.1.md) | Sep 4, 2026 | | Linux | libsoup sles 15.6 | 3.4.4-150600.3.47.1 | [SUSE-SU-2026:2314-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2314-1.md) | Jun 9, 2026 | | Linux | libsoup sles 15.7 | 3.4.4-150600.3.47.1 | [SUSE-SU-2026:2314-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2314-1.md) | Jun 9, 2026 | | Linux | libsoup sles 16.0 | 3.6.6-160000.2.1 | [SUSE-SU-2026:21998-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21998-1.md) | May 29, 2026 | | Linux | libsoup-3.0-0 Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | [libsoup-3.0-0 3.4.4-5ubuntu0.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libsoup-3.0-0-3.4.4-5ubuntu0.9.md) | Sep 4, 2026 | | Linux | libsoup-3.0-0 Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | [libsoup-3.0-0 3.6.6-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libsoup-3.0-0-3.6.6-1ubuntu0.1.md) | Sep 4, 2026 | | Linux | libsoup-3.0-common Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | [libsoup-3.0-common 3.4.4-5ubuntu0.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libsoup-3.0-common-3.4.4-5ubuntu0.9.md) | Sep 4, 2026 | | Linux | libsoup-3.0-common Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | [libsoup-3.0-common 3.6.6-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libsoup-3.0-common-3.6.6-1ubuntu0.1.md) | Sep 4, 2026 | | Linux | libsoup-3.0-tests Ubuntu 24.04.5 LTS (noble) | 3.4.4-5ubuntu0.9 | [libsoup-3.0-tests 3.4.4-5ubuntu0.9](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libsoup-3.0-tests-3.4.4-5ubuntu0.9.md) | Sep 4, 2026 | | Linux | libsoup-3.0-tests Ubuntu 26.04.1 LTS (resolute) | 3.6.6-1ubuntu0.1 | [libsoup-3.0-tests 3.6.6-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libsoup-3.0-tests-3.6.6-1ubuntu0.1.md) | Sep 4, 2026 | | Linux | libsoup3 RHEL 10 | 3.6.5-3.el10_0.15 | [RHSA-2026:17482](https://patchblox.com/security/data/fix/linux/rhsa-2026-17482.md) | Mar 30, 2026 | | Linux | libsoup3 almalinux 10 | 3.6.5-3.el10_2.11 | [ALSA-2026:19143](https://patchblox.com/security/data/fix/linux/alsa-2026-19143.md) | May 19, 2026 | | Linux | libsoup3 ol 10 | 0:3.6.5-3.el10_1.11 | [ELSA-2026-15968](https://patchblox.com/security/data/fix/linux/elsa-2026-15968.md) | May 11, 2026 | | Linux | libsoup3 rocky 10 | 0:3.6.5-3.el10_1.11 | [RLSA-2026:15968](https://patchblox.com/security/data/fix/linux/rlsa-2026-15968.md) | May 13, 2026 | | Linux | libsoup3-devel almalinux 10 | 3.6.5-3.el10_2.11 | [ALSA-2026:19143](https://patchblox.com/security/data/fix/linux/alsa-2026-19143.md) | May 19, 2026 | | Linux | libsoup3-devel ol 10 | 0:3.6.5-3.el10_1.11 | [ELSA-2026-15968](https://patchblox.com/security/data/fix/linux/elsa-2026-15968.md) | May 11, 2026 | | Linux | libsoup3-doc almalinux 10 | 3.6.5-3.el10_2.11 | [ALSA-2026:19143](https://patchblox.com/security/data/fix/linux/alsa-2026-19143.md) | May 19, 2026 | | Linux | libsoup3-doc ol 10 | 0:3.6.5-3.el10_1.11 | [ELSA-2026-15968](https://patchblox.com/security/data/fix/linux/elsa-2026-15968.md) | May 11, 2026 | --- Data as of 2026-11-08T00:53:09Z UTC. 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