CVE-2026-31873
NONE
GHSA-5339-hvwr-7582
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
Lifecycle Timeline
3Tags
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.
Analysis
The `link.href` check in `makeTagSafe` (safe.ts, line 68-71) uses `String.includes()`, which is case-sensitive: ```typescript if (key === 'href') { if (val.includes('javascript:') || val.includes('data:')) { return } next[key] = val } ``` 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`. …
Sign in for full analysis, threat intelligence, and remediation guidance.
Priority Score
Share
External POC / Exploit Code
Leaving vuln.today