CVE-2026-45305

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

Published: Jul 14, 2026Updated: Jul 15, 2026 Sources: CVE List NVDCWE-1333

7.5HIGH

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:HAvailability

High

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Weaknesses

CWE-1333

Affected Products

symfony

oss-projectaka symfony framework, twig (related)

symfonyLibrary

OSS Libraries / web-framework

yamlLibrary

OSS Libraries / web-framework

sensiolabs

oss-project

symfonyLibraryLibrary

OSS Libraries / generic-library

Exploitability

Official Patch Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Impact

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References

https://github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cb

github.com

https://github.com/symfony/symfony/releases/tag/v5.4.52

github.com

https://github.com/symfony/symfony/releases/tag/v6.4.40

github.com

and 3 more references View all →

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