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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
NVD MITRE
EPSS Score
0.8%
Top 46.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
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
View detailed technique mapping

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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