{"id":"CVE-2026-41305","aliases":["GHSA-qx2v-qp2m-jg93"],"url":"https://o3.security/vulnerability/CVE-2026-41305","summary":"PostCSS has XSS via Unescaped </style> in its CSS Stringify Output","details":"PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Versions prior to 8.5.10 do not escape `</style>` sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML `<style>` tags, `</style>` in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.","published":"2026-04-24T02:27:47.719Z","modified":"2026-08-07T11:50:18.242890158Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":{"score":0.00205,"percentile":0.10606,"asOf":"2026-08-09"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"postcss","fixedVersion":"8.5.10"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/postcss/postcss/releases/tag/8.5.10"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41305.json"},{"type":"ADVISORY","url":"https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41305"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:18.242890158Z"}}