What is CVE-2026-116891?

CVE-2026-116891 is a medium-severity vulnerability in Semanticmediawiki, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-10-27.

How severe is CVE-2026-116891?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Semanticmediawiki

CVE-2026-116891

SemanticMediaWiki from 4.2.0 before 7.2.1 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject HTML via unescaped cstate parameters in Special:FacetedSearch. Attackers can craft URLs with q, a matching crc32 csum or filtered=1, and cstate values that break out of hidden input attributes to execute script in victims' browsers.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-10-27 · last modified 2026-10-27.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Semanticmediawiki

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-9rcc-pm… (vendor-advisory)
www.vulncheck.com/advisories/semanticmediawiki-4.2.0-before-7.2.1-reflected-xss… (third-party-advisory)

Frequently asked questions

What is CVE-2026-116891?: CVE-2026-116891 is a medium-severity vulnerability in Semanticmediawiki, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-10-27.
How severe is CVE-2026-116891?: Medium severity. CVSS v3 base score is 6.1 out of 10.