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

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Summary

CVECVE-2026-45305
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-14 19:17:07 UTC
Updated2026-07-15 14:57:02 UTC
DescriptionSymfony 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.

Risk And Classification

Primary CVSS: v4.0 8.7 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.006630000 probability, percentile 0.475380000 (date 2026-07-15)

Problem Types: CWE-1333 | CWE-1333 CWE-1333: Inefficient Regular Expression Complexity

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Primary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Sensiolabs Symfony All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Symfony Symfony affected < 5.4.52 Not specified
CNA Symfony Symfony affected >= 6.0.0-BETA1, < 6.4.40 Not specified
CNA Symfony Symfony affected >= 7.0.0-BETA1, < 7.4.12 Not specified
CNA Symfony Symfony affected >= 8.0.0-BETA1, < 8.0.12 Not specified
CNA Symfony Yaml affected < 5.4.52 Not specified
CNA Symfony Yaml affected >= 6.0.0-BETA1, < 6.4.40 Not specified
CNA Symfony Yaml affected >= 7.0.0-BETA1, < 7.4.12 Not specified
CNA Symfony Yaml affected >= 8.0.0-BETA1, < 8.0.12 Not specified

References

ReferenceSourceLinkTags
github.com/symfony/symfony/security/advisories/GHSA-9frc-8383-795m [email protected] github.com Patch, Vendor Advisory
github.com/symfony/symfony/releases/tag/v5.4.52 [email protected] github.com Product, Release Notes
github.com/symfony/symfony/releases/tag/v6.4.40 [email protected] github.com Product, Release Notes
github.com/symfony/symfony/releases/tag/v8.0.12 [email protected] github.com Product, Release Notes
github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cb [email protected] github.com Patch
github.com/symfony/symfony/releases/tag/v7.4.12 [email protected] github.com Product, Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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