# CVE-2025-11683: libyaml-syck-perl: YAML::Syck versions before 1.36 for Perl has missing null-terminators whichcauses out-of-bounds read and potential in...

CVE-2025-11683 is fixed in 4 products on 1 platform, first by libyaml-syck-perl 1.29-1ubuntu0.18.04.1~esm1, released October 15, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-11683
- Priority: Routine
- CVSS: 6.5 (Medium)
- EPSS: 0.0031
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 15, 2025

## Description

YAML::Syck versions before 1.36 for Perl has missing null-terminators whichcauses out-of-bounds read and potential information disclosureMissing null terminators in token.c leads to but-of-bounds read whichallows adjacent variable to be readThe issue is seen with complex YAML files with a hash of all keys and emptyvalues.  There is no indication that the issue leads to accessing memoryoutside that allocated to the module.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libyaml-syck-perl Debian 12.15 (bookworm) | 1.34-2+deb12u1 | [DEBIAN-CVE-2025-11683](https://patchblox.com/security/data/fix/linux/debian-cve-2025-11683.md) | Oct 16, 2025 |
| Linux | libyaml-syck-perl Debian 13.5 (trixie) | 1.34-2+deb13u1 | [DEBIAN-CVE-2025-11683](https://patchblox.com/security/data/fix/linux/debian-cve-2025-11683.md) | Oct 16, 2025 |
| Linux | libyaml-syck-perl Debian 14 | 1.34-4 | [DEBIAN-CVE-2025-11683](https://patchblox.com/security/data/fix/linux/debian-cve-2025-11683.md) | Oct 16, 2025 |
| Linux | libyaml-syck-perl Ubuntu 18.04.6 LTS (bionic) | 1.29-1ubuntu0.18.04.1~esm1 | [libyaml-syck-perl 1.29-1ubuntu0.18.04.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libyaml-syck-perl-1.29-1ubuntu0.18.04.1-esm1.md) | Oct 15, 2025 |
| Linux | libyaml-syck-perl Ubuntu 20.04 LTS (focal) | 1.31-1ubuntu0.1~esm1 | [libyaml-syck-perl 1.31-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libyaml-syck-perl-1.31-1ubuntu0.1-esm1.md) | Oct 15, 2025 |
| Linux | libyaml-syck-perl Ubuntu 22.04.1 LTS (jammy) | 1.34-1ubuntu0.1~esm1 | [libyaml-syck-perl 1.34-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libyaml-syck-perl-1.34-1ubuntu0.1-esm1.md) | Oct 15, 2025 |
| Linux | libyaml-syck-perl Ubuntu 24.04.5 LTS (noble) | 1.34-2ubuntu0.24.04.1~esm1 | [libyaml-syck-perl 1.34-2ubuntu0.24.04.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libyaml-syck-perl-1.34-2ubuntu0.24.04.1-esm1.md) | Oct 15, 2025 |
| Linux | libyaml-syck-perl Ubuntu 25.04 (plucky) | 1.34-2ubuntu0.25.04.1 | [libyaml-syck-perl 1.34-2ubuntu0.25.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libyaml-syck-perl-1.34-2ubuntu0.25.04.1.md) | Jan 16, 2026 |
| Linux | libyaml-syck-perl Ubuntu 25.10 (questing) | 1.34-3ubuntu0.1 | [libyaml-syck-perl 1.34-3ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libyaml-syck-perl-1.34-3ubuntu0.1.md) | Oct 15, 2025 |
| Linux | perl-YAML-Syck amzn 2023 | 1.36-1.amzn2023.0.1 | [ALAS2023-2025-1248](https://patchblox.com/security/data/fix/linux/alas2023-2025-1248.md) | Oct 27, 2025 |
| Linux | perl-YAML-Syck opensuse-leap 16.0 | 1.470.0-bp160.1.1 | [OPENSUSE-SU-2026:21497-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21497-1.md) | Jul 29, 2026 |
| Linux | perl-YAML-Syck-debuginfo amzn 2023 | 1.36-1.amzn2023.0.1 | [ALAS2023-2025-1248](https://patchblox.com/security/data/fix/linux/alas2023-2025-1248.md) | Oct 27, 2025 |
| Linux | perl-YAML-Syck-debugsource amzn 2023 | 1.36-1.amzn2023.0.1 | [ALAS2023-2025-1248](https://patchblox.com/security/data/fix/linux/alas2023-2025-1248.md) | Oct 27, 2025 |

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Data as of 2026-11-08T19:12:23Z 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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