{"id":"CVE-2026-45304","aliases":["GHSA-4qpc-3hr4-r2p4"],"url":"https://o3.security/vulnerability/CVE-2026-45304","summary":"Symfony: YAML Parser Exponential Memory Allocation via Recursive Collection-Alias Expansion (\"Billion Laughs\")","details":"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.","published":"2026-07-14T18:48:49.329Z","modified":"2026-08-12T03:51:15.741472499Z","cvss":null,"epss":{"score":0.00804,"percentile":0.54012,"asOf":"2026-08-21"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"symfony/yaml","fixedVersion":"5.4.52"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"5.4.52"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"6.4.40"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"7.4.12"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"8.0.12"},{"ecosystem":"Packagist","name":"symfony/yaml","fixedVersion":"6.4.40"},{"ecosystem":"Packagist","name":"symfony/yaml","fixedVersion":"7.4.12"},{"ecosystem":"Packagist","name":"symfony/yaml","fixedVersion":"8.0.12"}],"fix":{"url":"https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a","label":"symfony/symfony@e77391b"},"references":[{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v5.4.52"},{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v6.4.40"},{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v7.4.12"},{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v8.0.12"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45304.json"},{"type":"ADVISORY","url":"https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45304"},{"type":"FIX","url":"https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:15.741472499Z"}}