CVE-2026-45305
highpriority · track · 30EPSS 0.007 · 52 %ileDEEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–8.7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
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affected products (22)
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advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1805Zabbix: Mehrere SchwachstellenDeutsch2026-06-04csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Zabbix ausnutzen, um einen Denial of Service Angriff durchzuführen, und um Sicherheitsvorkehrungen zu umgehen.
- GHSA-9frc-8383-795mSymfony's YAML Parser has a ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex2026-05-27ghsa · osvUS
### Description `Symfony\Component\Yaml\Parser::cleanup()` strips the optional `%YAML` directive header, leading comments, and document start/end markers before parsing. The original regexes contained overlapping quantifiers, most notably `'#^%YAML[: ][\d.]+.*\n#u'`, whose `[\d.]+` and `.*` overlap on the dot, that exhibit catastrophic backtracking on crafted input. A single oversized `%YAML` directive header (or comment / document-marker line) makes the parser hang for an arbitrarily long time, denying service. ### Resolution The four regexes in `Parser::cleanup()` (YAML directive header, leading comments, document-start marker, document-end marker) have been rewritten with possessive quantifiers and unambiguous character classes so backtracking cannot occur. The patch for this issue is available [here](https://github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cb) for branch 5.4. ### Credits Symfony would like to thank Pietro Tirenna (Shielder) for reporting the issue and Nicolas Grekas for fixing it.
also known as (3)
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sources
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references (19)
External citations — patches, advisories, analysis.
- https://github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cbcnnvd
- https://github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cb,https://github.com/symfony/symfony/security/advisories/GHSA-9frc-8383-795mPatchcnnvd
- https://github.com/symfony/symfony/releases/tag/v5.4.52cnnvd
- https://github.com/symfony/symfony/releases/tag/v6.4.40cnnvd
- https://github.com/symfony/symfony/releases/tag/v7.4.12cnnvd
- https://github.com/symfony/symfony/releases/tag/v8.0.12cnnvd
- https://github.com/symfony/symfony/security/advisories/GHSA-9frc-8383-795mcnnvd
- https://github.com/symfony/symfony/commit/9749cd43c5e09b3735093623670b21b9d8a056cbenisa_euvd
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