{"action":"Upgrade symfony/symfony to 5.4.52 or later.","affected":[{"fixed":"5.4.52","introduced":"0"},{"fixed":"6.4.40","introduced":"6.0.0"},{"fixed":"7.4.12","introduced":"7.0.0"},{"fixed":"8.0.12","introduced":"8.0.0"}],"component":"symfony/symfony","cve_ids":["CVE-2026-45304"],"ecosystem":"Packagist","epss":0.00684,"exploited":false,"fixed_versions":["5.4.52","6.4.40","7.4.12","8.0.12"],"ghsa_id":"GHSA-4qpc-3hr4-r2p4","id":"tcs_01M5KEV7ABKX6GNBNFJKQ0M0QR","modified_at":"2026-09-10T03:50:45.630970551Z","published_at":"2026-05-27T21:33:50Z","references":["https://osv.dev/vulnerability/GHSA-4qpc-3hr4-r2p4","https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4","https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a","https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45304.yaml","https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/yaml/CVE-2026-45304.yaml","https://github.com/symfony/symfony","https://symfony.com/cve-2026-45304"],"severity":{"label":"high","score":7.5},"sources":[{"source":"osv","source_id":"GHSA-4qpc-3hr4-r2p4#Packagist/symfony/symfony","url":"https://osv.dev/vulnerability/GHSA-4qpc-3hr4-r2p4"},{"source":"nvd","source_id":"CVE-2026-45304","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45304"}],"summary":"Symfony's YAML Parser Vulnerable to Exponential Memory Allocation via Recursive Collection-Alias Expansion (\"Billion Laughs\")"}