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CVE-2026-39315

nvd nist
Published: Apr 9, 2026Modified: Jun 17, 2026

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6.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Exploitability: 2.8 / Impact: 2.7
Source: security-advisories@github.com (Secondary)

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 (1)

Products: Unjs: Unhead
Unjs
1 product
Unhead
Configuration A
1 vulnerable
Vulnerable SoftwareAffected Versions
Unhead
Before 2.1.13

Related CWEs

CWE-184
Incomplete List of Disallowed Inputs
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete, leading to resultant weaknesses.

References (4)

Source: security-advisories@github.com
Patch
Source: security-advisories@github.com
ProductRelease Notes
Source: security-advisories@github.com
ExploitMitigationVendor Advisory
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
ExploitMitigationVendor Advisory

Timeline

No history available yet.