# CVE-2025-40908: perl-YAML-LibYAML: Kirill Siminov's "libyaml" is arguably the best YAML implementation

CVE-2025-40908 is fixed in 4 products on 1 platform, first by libyaml-libyaml-perl 0.83+ds-1ubuntu0.22.04.1, released June 1, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-40908
- Priority: High
- CVSS: 9.1 (Important)
- EPSS: 0.0047
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 1, 2025

## Description

Kirill Siminov's "libyaml" is arguably the best YAML implementation. The C library is written precisely to the YAML 1.1 specification. It was originally bound to Python and was later bound to Ruby.  Security Fix(es):  * yaml-libyaml: LibYAML Perl File Modification Vulnerability (CVE-2025-40908)  For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libyaml-libyaml-perl Debian 12.15 (bookworm) | 0.86+ds-1+deb12u1 | [DEBIAN-CVE-2025-40908](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40908.md) | Jun 1, 2025 |
| Linux | libyaml-libyaml-perl Debian 13.5 (trixie) | 0.903.0+ds-1 | [DEBIAN-CVE-2025-40908](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40908.md) | Jun 1, 2025 |
| Linux | libyaml-libyaml-perl Debian 14 | 0.903.0+ds-1 | [DEBIAN-CVE-2025-40908](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40908.md) | Jun 1, 2025 |
| Linux | libyaml-libyaml-perl Ubuntu 22.04.1 LTS (jammy) | 0.83+ds-1ubuntu0.22.04.1 | [libyaml-libyaml-perl 0.83+ds-1ubuntu0.22.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libyaml-libyaml-perl-0.83-ds-1ubuntu0.22.04.1.md) | Jun 1, 2025 |
| Linux | libyaml-libyaml-perl Ubuntu 24.04.5 LTS (noble) | 0.89+ds-1ubuntu0.24.04.1 | [libyaml-libyaml-perl 0.89+ds-1ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libyaml-libyaml-perl-0.89-ds-1ubuntu0.24.04.1.md) | Jun 1, 2025 |
| Linux | perl-YAML-LibYAML RHEL 8 | 1:0.70-2.el8_10 | [RHSA-2025:9329](https://patchblox.com/security/data/fix/linux/rhsa-2025-9329.md) | Jun 23, 2025 |
| Linux | perl-YAML-LibYAML RHEL 9 | 1:0.82-6.1.el9_6 | [RHSA-2025:9330](https://patchblox.com/security/data/fix/linux/rhsa-2025-9330.md) | Jun 23, 2025 |
| Linux | perl-YAML-LibYAML almalinux 8 | 1:0.70-2.el8_10 | [ALSA-2025:9329](https://patchblox.com/security/data/fix/linux/alsa-2025-9329.md) | Jun 23, 2025 |
| Linux | perl-YAML-LibYAML almalinux 9 | 1:0.82-6.1.el9_6 | [ALSA-2025:9330](https://patchblox.com/security/data/fix/linux/alsa-2025-9330.md) | Jun 23, 2025 |
| Linux | perl-YAML-LibYAML amzn 2023 | 1:0.82-4.amzn2023.0.3 | [ALAS2023-2025-1036](https://patchblox.com/security/data/fix/linux/alas2023-2025-1036.md) | Jun 18, 2025 |
| Linux | perl-YAML-LibYAML ol 8 | 1:0.70-2.el8_10 | [ELSA-2025-9329](https://patchblox.com/security/data/fix/linux/elsa-2025-9329.md) | Jun 24, 2025 |
| Linux | perl-YAML-LibYAML ol 9 | 1:0.82-6.1.el9_6 | [ELSA-2025-9330](https://patchblox.com/security/data/fix/linux/elsa-2025-9330.md) | Jun 23, 2025 |
| Linux | perl-YAML-LibYAML opensuse-leap 15.6 | 0.904.0-150000.3.16.1 | [SUSE-RU-2025:03081-1](https://patchblox.com/security/data/fix/linux/suse-ru-2025-03081-1.md) | Sep 5, 2025 |
| Linux | perl-YAML-LibYAML rocky 8 | 1:0.70-2.el8_10 | [RLSA-2025:9329](https://patchblox.com/security/data/fix/linux/rlsa-2025-9329.md) | Jul 29, 2025 |
| Linux | perl-YAML-LibYAML rocky 9 | 1:0.82-6.1.el9_6 | [RLSA-2025:9330](https://patchblox.com/security/data/fix/linux/rlsa-2025-9330.md) | Oct 4, 2025 |
| Linux | perl-YAML-LibYAML sles 15.6 | 0.904.0-150000.3.16.1 | [SUSE-RU-2025:03081-1](https://patchblox.com/security/data/fix/linux/suse-ru-2025-03081-1.md) | Sep 5, 2025 |
| Linux | perl-YAML-LibYAML sles 15.7 | 0.904.0-150000.3.16.1 | [SUSE-RU-2025:03081-1](https://patchblox.com/security/data/fix/linux/suse-ru-2025-03081-1.md) | Sep 5, 2025 |
| Linux | perl-YAML-LibYAML-debuginfo amzn 2023 | 1:0.82-4.amzn2023.0.3 | [ALAS2023-2025-1036](https://patchblox.com/security/data/fix/linux/alas2023-2025-1036.md) | Jun 18, 2025 |
| Linux | perl-YAML-LibYAML-debugsource amzn 2023 | 1:0.82-4.amzn2023.0.3 | [ALAS2023-2025-1036](https://patchblox.com/security/data/fix/linux/alas2023-2025-1036.md) | Jun 18, 2025 |

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