# CVE-2026-5089: libyaml-syck-perl: YAML::Syck versions before 1.38 for Perl  has an out-of-bounds read

CVE-2026-5089 is fixed in 5 products on 1 platform, first by ALAS2023-2026-1769, released May 25, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-5089
- Priority: High
- CVSS: 7.3 (high)
- EPSS: 0.0040
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 12, 2026

## Description

YAML::Syck versions before 1.38 for Perl  has an out-of-bounds read.  The base60 (sexagesimal) parsing code in perl_syck.h has a buffer underflow bug in both int#base60 and float#base60 handlers. When processing the leftmost segment of a colon-separated value (e.g., the 1 in 1:30:45), the inner while loop can decrement a pointer past the start of the string buffer:      while ( colon >= ptr && *colon != ':' )     {         colon--;     }     if ( *colon == ':' ) *colon = '\0';  // colon may be ptr-1 here  When no colon is found (final/leftmost segment), colon becomes ptr-1, and the subsequent *colon dereference reads one byte before the allocated buffer.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libyaml-syck-perl Debian 12.15 (bookworm) | 1.34-2+deb12u3 | [DEBIAN-CVE-2026-5089](https://patchblox.com/security/data/fix/linux/debian-cve-2026-5089.md) | May 27, 2026 |
| Linux | libyaml-syck-perl Debian 13.5 (trixie) | 1.34-2+deb13u3 | [DEBIAN-CVE-2026-5089](https://patchblox.com/security/data/fix/linux/debian-cve-2026-5089.md) | May 27, 2026 |
| Linux | libyaml-syck-perl Debian 14 | 1.36-3 | [DEBIAN-CVE-2026-5089](https://patchblox.com/security/data/fix/linux/debian-cve-2026-5089.md) | May 27, 2026 |
| Linux | perl-YAML-Syck amzn 2023 | 1.37-1.amzn2023.0.3 | [ALAS2023-2026-1769](https://patchblox.com/security/data/fix/linux/alas2023-2026-1769.md) | May 25, 2026 |
| Linux | perl-YAML-Syck opensuse-leap 16.0 | 1.450.0-bp160.2.1 | [OPENSUSE-SU-2026:20938-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20938-1.md) | Jun 10, 2026 |
| Linux | perl-YAML-Syck-debuginfo amzn 2023 | 1.37-1.amzn2023.0.3 | [ALAS2023-2026-1769](https://patchblox.com/security/data/fix/linux/alas2023-2026-1769.md) | May 25, 2026 |
| Linux | perl-YAML-Syck-debugsource amzn 2023 | 1.37-1.amzn2023.0.3 | [ALAS2023-2026-1769](https://patchblox.com/security/data/fix/linux/alas2023-2026-1769.md) | May 25, 2026 |
| Linux | perl-YAML-Syck-tests amzn 2023 | 1.37-1.amzn2023.0.3 | [ALAS2023-2026-1769](https://patchblox.com/security/data/fix/linux/alas2023-2026-1769.md) | May 25, 2026 |

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Data as of 2026-11-08T00:53:09Z 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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