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CVE-2026-31873

CVE-2026-31873 · Unhead has a Bypass of URI Scheme Sanitization in makeTagSafe via Case-Sensitivity

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 0.0 · Low · EPSS 0.2% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • unhead

    Versions
    • < 2.1.11: Affected

    No fix published

  • unhead npm

    Affected ranges
    • SEMVER: < 2.1.11

    Update to 2.1.11

Original sources

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