CVEvulnerability

CVE-2026-39315

6.1 MEDIUM Published 2026-04-09 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-04-09
Last modified
2026-10-26
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.1 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weaknesses
CWE-184

Description

Unhead is a document head and template manager. Prior to 2.1.13, useHeadSafe() is the composable that Nuxt's own documentation explicitly recommends for rendering user-supplied content in <head> safely. Internally, the hasDangerousProtocol() function in packages/unhead/src/plugins/safe.ts decodes HTML entities before checking for blocked URI schemes (javascript:, data:, vbscript:). The decoder uses two regular expressions with fixed-width digit caps. The HTML5 specification imposes no limit on leading zeros in numeric character references. When a padded entity exceeds the regex digit cap, the decoder silently skips it. The undecoded string is then passed to startsWith('javascript:'), which does not match. makeTagSafe() writes the raw value directly into SSR HTML output. The browser's HTML parser decodes the padded entity natively and constructs the blocked URI. This vulnerability is fixed in 2.1.13.

Affected configurations

• unjs unhead (< 2.1.13)

Related

Weakness · CWE (1)

  • CWE-184 Incomplete List of Disallowed Inputs weakness

References