# CVE-2019-25777: libyaml-perl: YAML versions before 1.27_001 for Perl allow a loaded perl/glob document to replace any package variable, which can l...

CVE-2019-25777 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2019-25777, released October 5, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2019-25777
- Priority: High
- CVSS: 8.1 (high)
- EPSS: 0.0035
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 5, 2026

## Description

YAML versions before 1.27_001 for Perl allow a loaded perl/glob document to replace any package variable, which can lead to arbitrary code execution.  A perl/glob document names a package and a symbol, and supplies the value assigned to it. Nothing restricts the name, so the target can be @INC or YAML's own load options.  A perl/glob document that sets $YAML::LoadCode or $YAML::UseCode turns on code loading, which is off by default, for every later Load() in the process. A perl/code document is then passed to a string eval, so an attacker who supplies two documents to separate Load() calls in one process can execute arbitrary Perl code.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libyaml-perl Debian 12.15 (bookworm) | 1.29-1 | [DEBIAN-CVE-2019-25777](https://patchblox.com/security/data/fix/linux/debian-cve-2019-25777.md) | Oct 5, 2026 |
| Linux | libyaml-perl Debian 13.5 (trixie) | 1.29-1 | [DEBIAN-CVE-2019-25777](https://patchblox.com/security/data/fix/linux/debian-cve-2019-25777.md) | Oct 5, 2026 |
| Linux | libyaml-perl Debian 14 | 1.29-1 | [DEBIAN-CVE-2019-25777](https://patchblox.com/security/data/fix/linux/debian-cve-2019-25777.md) | Oct 5, 2026 |
| Linux | libyaml-perl Ubuntu 18.04.6 LTS (bionic) | 1.24-1ubuntu0.1~esm1 | [libyaml-perl 1.24-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libyaml-perl-1.24-1ubuntu0.1-esm1.md) | Oct 16, 2026 |
| Linux | perl-YAML RHEL 8 | 0:1.24-4.module+el8.10.0+25073+d1062575 | [RHSA-2026:93471](https://patchblox.com/security/data/fix/linux/rhsa-2026-93471.md) | Nov 3, 2026 |
| Linux | perl-YAML almalinux 8 | 1.24-4.module_el8.10.0+4341+ab0ec422 | [ALSA-2026:93471](https://patchblox.com/security/data/fix/linux/alsa-2026-93471.md) | Nov 7, 2026 |
| Linux | perl-YAML ol 8 | 0:1.24-4.module+el8.10.0+91104+f3b3492f | [ELSA-2026-93471](https://patchblox.com/security/data/fix/linux/elsa-2026-93471.md) | Nov 7, 2026 |
| Linux | perl-YAML rocky 8 | 0:1.24-4.module+el8.10.0+40403+bd06a93a | [RLSA-2026:93471](https://patchblox.com/security/data/fix/linux/rlsa-2026-93471.md) | Nov 7, 2026 |

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Data as of 2026-11-08T13:06:02Z 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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