CVE record
CVE-2026-45305
Symfony: YAML Parser ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex
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.
CVE evidence
Known exploitation
Not listed in fetched KEV catalog
Absence from the fetched catalog does not establish that exploitation has not occurred.
Severity
high
CVSS 8.7 · CVSS_V4
Affected packages
2
Supported package records returned by OSV. Vendor and product names are not used to infer matches.
OSV package mapping
Affected open-source packages
| Package | Ecosystem | Fixed versions |
|---|---|---|
| symfony/yaml | composer | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |
| symfony/symfony | composer | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |