---
id: CVE-2019-25777
title: >-
  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 …
summary: >-
  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 …
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-502
  - CWE-914
product: YAML
affected:
  - YAML < 1.27_001
published: '2026-10-05'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T17:17:09.893'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2019-25777'
references:
  - url: >-
      https://github.com/ingydotnet/yaml-pm/commit/bace96b5e6661d521c7c515c94a09e081c911fce.patch
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'https://github.com/ingydotnet/yaml-pm/issues/212'
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'https://metacpan.org/release/TINITA/YAML-1.28/changes'
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'http://www.openwall.com/lists/oss-security/2026/10/05/7'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2019/cve-2019-25777.json
  - url: 'https://access.redhat.com/security/cve/CVE-2019-25777'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2545818'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2019-25777'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2019-25777'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-06T16:58:07.558999Z'
epss: 0.00352
epssPercentile: 0.28659
ingestedAt: '2026-10-05T07:14:48.255Z'
vendor: Red Hat
scores:
  nvd: 7.3
  vendor: 8.1
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-06 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2019/cve-2019-25777.json)