CVE-2026-31873Disclosure(unjs / unhead)

LOWCVSS 6.1 · MEDIUM

Signal is active with 1 mentions in latest observed window

Immediate actions

Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browsers treat URI schemes case-insensitively. DATA:text/css,... is the same as data:text/css,... to the browser, but 'DATA:...'.includes('data:') returns false. An attacker can inject arbitrary CSS for UI redressing or data exfiltration via CSS attribute selectors with background-image callbacks. This vulnerability is fixed in 2.1.11.

unjs CVEs Back to dashboard

0.0/ 10 priority

Sources & remediation

Exploit / PoC references

https://github.com/unjs/unhead/security/advisories/GHSA-5339-hvwr-7582

Weakness type (CWE)

CWE-79

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

NONE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

unhead

Threat summary

2 mentions across 2 observed days
Momentum state: stable

What's happening

Technical details provided in 1 signal
Disclosure: 2 classified signals
Peaked 1d ago at 1 mentions (2026-03-12); latest day: 1
2 total mentions across 2 days

Affected systems

Vendors

unjs

Products

unhead

Deep dive

Activity timeline2 mentions / 2d

Signal classification1 categories

Disclosure

2100.0%

Referenced assets3 URLs

By indicator

Full discourse2 posts

Vulmon Vulnerability Feed@VulmonFeeds212d
Disclosure
CVE-2026-31873 Unhead CSS Injection Vulnerability via Case-Sensitive URI... https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-31873 Don't wait vulnerability scanning results: https://alerts.vulmon.com/?utm_source=twitter&utm_medium=social&utm_campaign=2102281&utm_content=2
Post summary
A brief announcement of CVE-2026-31873 describing a CSS injection via case-sensitive URI, linked to a vulnerability details page, but without technical depth, exploit code, or mitigation information.
0001060
4.0K followersView on X
CVE@CVEnew212d
Disclosure
CVE-2026-31873 Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browser… https://www.cve.org/CVERecord?id=CVE-2026-31873
Post summary
CVE-2026-31873 is a disclosed vulnerability in Unhead’s makeTagSafe function, where the case-sensitive use of String.includes() for link.href checks allows potential exploitation. No PoC, exploit, or patch information is provided.
00000130
56.7K followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	unjs	unhead	-	-	-

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