{"id":"CVE-2026-31873","state":"PUBLISHED","title":"Unhead has a Bypass of URI Scheme Sanitization in makeTagSafe via Case-Sensitivity","description":"Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browsers treat URI schemes case-insensitively. DATA:text/css,... is the same as data:text/css,... to the browser, but 'DATA:...'.includes('data:') returns false. An attacker can inject arbitrary CSS for UI redressing or data exfiltration via CSS attribute selectors with background-image callbacks. This vulnerability is fixed in 2.1.11.","publishedAt":"2026-03-12T17:20:35.660Z","updatedAt":"2026-03-12T17:46:46.723Z","severity":{"score":0,"label":"None","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["unjs unhead"],"affected":[{"vendor":"unjs","product":"unhead","versions":[{"version":"< 2.1.11","status":"affected"}]}],"references":["https://github.com/unjs/unhead/security/advisories/GHSA-5339-hvwr-7582"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31873.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31873","state":"PUBLISHED","datePublished":"2026-03-12T17:20:35.660Z","dateUpdated":"2026-03-12T17:46:46.723Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-09T19:02:25.014Z"},"containers":{"cna":{"title":"Unhead has a Bypass of URI Scheme Sanitization in makeTagSafe via Case-Sensitivity","descriptions":[{"lang":"en","value":"Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browsers treat URI schemes case-insensitively. DATA:text/css,... is the same as data:text/css,... to the browser, but 'DATA:...'.includes('data:') returns false. An attacker can inject arbitrary CSS for UI redressing or data exfiltration via CSS attribute selectors with background-image callbacks. This vulnerability is fixed in 2.1.11."}],"affected":[{"vendor":"unjs","product":"unhead","versions":[{"version":"< 2.1.11","status":"affected"}]}],"references":[{"url":"https://github.com/unjs/unhead/security/advisories/GHSA-5339-hvwr-7582","name":"https://github.com/unjs/unhead/security/advisories/GHSA-5339-hvwr-7582","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":0,"baseSeverity":"NONE","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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":"2026-03-12T17:20:35.660Z"},"source":{"advisory":"GHSA-5339-hvwr-7582","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-12T17:46:23.897133Z","id":"CVE-2026-31873","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-12T17:46:46.723Z"}}]}}}