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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
symfony symfony affected
Version Status Constraints
< 5.4.52 affected —
>= 6.0.0-BETA1, < 6.4.40 affected —
>= 7.0.0-BETA1, < 7.4.12 affected —
>= 8.0.0-BETA1, < 8.0.12 affected —
symfony yaml affected
Version Status Constraints
< 5.4.52 affected —
>= 6.0.0-BETA1, < 6.4.40 affected —
>= 7.0.0-BETA1, < 7.4.12 affected —
>= 8.0.0-BETA1, < 8.0.12 affected —

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Project Subscriptions

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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
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cb cve-icon
https://github.com/symfony/symfony/releases/tag/v5.4.52 cve-icon
https://github.com/symfony/symfony/releases/tag/v6.4.40 cve-icon
https://github.com/symfony/symfony/releases/tag/v7.4.12 cve-icon
https://github.com/symfony/symfony/releases/tag/v8.0.12 cve-icon
https://github.com/symfony/symfony/security/advisories/GHSA-9frc-8383-795m cve-icon
History

Tue, 14 Jul 2026 19:00:00 +0000

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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-14T18:50:14.830Z

Reserved: 2026-05-11T20:14:43.202Z

Link: CVE-2026-45305

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses