CVE-2026-31860

MEDIUM

unjs/unhead < 2.1.11 - Cross-Site Scripting via useHeadSafe() Attribute Injection

Title source: llm
STIX 2.1

Description

Unhead is a document head and template manager. Prior to 2.1.11, useHeadSafe() can be bypassed to inject arbitrary HTML attributes, including event handlers, into SSR-rendered <head> tags. This is the composable that Nuxt docs recommend for safely handling user-generated content. The acceptDataAttrs function (safe.ts, line 16-20) allows any property key starting with data- through to the final HTML. It only checks the prefix, not whether the key contains spaces or other characters that break HTML attribute parsing. This vulnerability is fixed in 2.1.11.

References (1)

Core 1
Core References

Scores

CVSS v3 6.1
EPSS 0.0026
EPSS Percentile 17.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-79
Status published
Products (1)
unjs/unhead < 2.1.11 (2 CPE variants)
Published Mar 12, 2026
Tracked Since Mar 13, 2026