CVE-2026-45305

Symfony: YAML Parser ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex

Published Jul 14, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser::cleanup() used regular expressions with overlapping quantifiers for YAML directive, comment, and document marker cleanup, allowing crafted input to make parsing hang for an arbitrarily long time. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-6312-1 symfony security update
Debian DSA Debian DSA DSA-6317-1 symfony security update
Github GHSA Github GHSA GHSA-9frc-8383-795m Symfony's YAML Parser has a ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex
History
Type Values Removed Values Added
First Time appeared Symfony
Symfony symfony
Symfony yaml
Vendors & Products Symfony
Symfony symfony
Symfony yaml
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser::cleanup() used regular expressions with overlapping quantifiers for YAML directive, comment, and document marker cleanup, allowing crafted input to make parsing hang for an arbitrarily long time. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Title Symfony: YAML Parser ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex
Weaknesses CWE-1333
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 15, 2026, 2:03 PM
Reserved
May 11, 2026, 8:14 PM
Status
Analyzed
Published
Jul 14, 2026, 7:17 PM
Modified
Jul 15, 2026, 2:57 PM