CVE-2026-45304
Published:July 14, 2026
Updated:July 21, 2026
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 resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Affected Packages
https://github.com/symfony/symfony.git (GITHUB):
Affected version(s) >=v8.0.0 <v8.0.12Fix Suggestion:
Update to version v8.0.12https://github.com/symfony/symfony.git (GITHUB):
Affected version(s) >=v7.4.0 <v7.4.12Fix Suggestion:
Update to version v7.4.12https://github.com/symfony/symfony.git (GITHUB):
Affected version(s) >=v6.4.0 <v6.4.40Fix Suggestion:
Update to version v6.4.40https://github.com/symfony/symfony.git (GITHUB):
Affected version(s) >=v2.0.0BETA1 <v5.4.52Fix Suggestion:
Update to version v5.4.52symfony/yaml (PHP):
Affected version(s) >=v7.0.0 <v7.4.12Fix Suggestion:
Update to version v7.4.12symfony/yaml (PHP):
Affected version(s) >=v6.0.0 <v6.4.40Fix Suggestion:
Update to version v6.4.40symfony/symfony (PHP):
Affected version(s) >=dev-add-security-skills <v5.4.52Fix Suggestion:
Update to version v5.4.52symfony/symfony (PHP):
Affected version(s) >=v8.0.0 <v8.0.12Fix Suggestion:
Update to version v8.0.12symfony/symfony (PHP):
Affected version(s) >=v7.0.0 <v7.4.12Fix Suggestion:
Update to version v7.4.12symfony/yaml (PHP):
Affected version(s) >=dev-issue-8145 <v5.4.52Fix Suggestion:
Update to version v5.4.52symfony/yaml (PHP):
Affected version(s) >=v8.0.0 <v8.0.12Fix Suggestion:
Update to version v8.0.12symfony/symfony (PHP):
Affected version(s) >=v6.0.0 <v6.4.40Fix Suggestion:
Update to version v6.4.40Related Resources (10)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
Exploit Maturity
UNREPORTED
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
EPSS
Base Score:
0.80