PT-2026-31676 · Npm+1 · Unhead

Cybe4Sent1Nel · Published 2026-04-09 · Updated 2026-04-10 · CVE-2026-39315

NVD

CVSS v3.1

6.1

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 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.

Exploit

Fix

Incomplete List of Disallowed Inputs

Weakness Enumeration

CWE-184

Related Identifiers

CVE-2026-39315

GHSA-95H2-GJ7X-GX9W

Affected Products

Unhead

References · 7

• 🔥 https://github.com/unjs/unhead/security/advisories/GHSA-95h2-gj7x-gx9w · Exploit
• https://github.com/unjs/unhead/commit/961ea781e091853812ffe17f8cda17105d2d2299 · Patch
• https://osv.dev/vulnerability/GHSA-95h2-gj7x-gx9w · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-39315 · Security Note
• https://github.com/unjs/unhead · Note
• https://github.com/unjs/unhead/releases/tag/v2.1.13 · Note
• https://reddit.com/r/VulnMatter/comments/1shkdl9/resumen_diario_de_vulnerabilidades_10042026 · Reddit Post