How severe is CVE-2026-31860?

CVE-2026-31860 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-31860 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-31860?

CVE-2026-31860 affects Unjs Unhead. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-31860?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-31860 have an EU (EUVD) identifier?

Yes. CVE-2026-31860 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11639.

When was CVE-2026-31860 published?

CVE-2026-31860 was published on 2026-03-12 and last updated on 2026-06-17.

CVE-2026-31860

CVE-2026-31860 is a medium-severity vulnerability in Unjs Unhead with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 5.3
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-11639
Weakness: CWE-79
Affected product: Unjs Unhead
Published: 2026-03-12
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-31860?: 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.
How severe is CVE-2026-31860?: CVE-2026-31860 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-31860 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31860?: CVE-2026-31860 affects Unjs Unhead. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-31860?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-31860 have an EU (EUVD) identifier?: Yes. CVE-2026-31860 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11639.
When was CVE-2026-31860 published?: CVE-2026-31860 was published on 2026-03-12 and last updated on 2026-06-17.

References

https://github.com/unjs/unhead/security/advisories/GHSA-g5xx-pwrp-g3fv

Affected products (1)

cpe:2.3:a:unjs:unhead:*:*:*:*:*:*:*:*

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