{"id":"CVE-2026-41305","state":"PUBLISHED","title":"PostCSS has XSS via Unescaped </style> in its CSS Stringify Output","description":"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.","publishedAt":"2026-04-24T02:27:47.719Z","updatedAt":"2026-04-24T16:23:41.198Z","severity":{"score":6.1,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["postcss postcss"],"affected":[{"vendor":"postcss","product":"postcss","versions":[{"version":"< 8.5.10","status":"affected"}]}],"references":["https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93","https://github.com/postcss/postcss/releases/tag/8.5.10"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/41xxx/CVE-2026-41305.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-41305","state":"PUBLISHED","datePublished":"2026-04-24T02:27:47.719Z","dateUpdated":"2026-04-24T16:23:41.198Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-20T14:01:46.670Z"},"containers":{"cna":{"title":"PostCSS has XSS via Unescaped </style> in its CSS Stringify Output","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"postcss","product":"postcss","versions":[{"version":"< 8.5.10","status":"affected"}]}],"references":[{"url":"https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93","name":"https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/postcss/postcss/releases/tag/8.5.10","name":"https://github.com/postcss/postcss/releases/tag/8.5.10","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.1,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-24T02:27:47.719Z"},"source":{"advisory":"GHSA-qx2v-qp2m-jg93","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-24T16:22:58.569354Z","id":"CVE-2026-41305","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-24T16:23:41.198Z"}}]}}}