CVE-2026-116891: SemanticMediaWiki from 4.2.0 before 7.2.1 contains a reflected cross-site scripting vulnerability that allows

Routine

MEDIUM 6.1UPGRADE

CVE-2026-116891 is a medium-severity flaw (CVSS 6.1) affecting semantic mediawiki. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-10-27
Last modified	2026-10-28

Publisher (CNA): VulnCheck · Vendor: semantic-mediawiki

Last updated 2026-10-28 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-27 11:17 UTCPublished CVE record published
2026-10-28 15:33 UTCUpdated Record last modified

semantic-mediawiki semantic mediawiki UPGRADE

Affected: >= 4.2.0 and < 7.2.1

Fixed in: 7.2.1

Safe to downgrade to: a release before 4.2.0

1. Check installed version

apt-cache policy semantic-mediawiki || rpm -q semantic-mediawiki || semantic-mediawiki --version

2. UPGRADE to 7.2.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade semantic-mediawiki

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade semantic-mediawiki

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.2.0 (Debian / Ubuntu)

apt-cache madison semantic-mediawiki sudo apt install semantic-mediawiki=<VERSION_BEFORE_4.2.0> sudo apt-mark hold semantic-mediawiki

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list semantic-mediawiki sudo dnf downgrade semantic-mediawiki-<VERSION_BEFORE_4.2.0> sudo dnf versionlock add semantic-mediawiki

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Advisories and coverage

Research and news

Vulners Bulletins: CVE-2026-116891 2026-10-27

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-116891?

semantic mediawiki: upgrade to 7.2.1. Exact commands for each OS are on this page.

Is CVE-2026-116891 being exploited?

CVE-2026-116891 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-116891 affect?

CVE-2026-116891 affects semantic mediawiki. Severity is medium (CVSS 6.1). 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

How urgent is CVE-2026-116891?

Priority 28/100. Public exploit reference

Related CVEs

CVE-2026-116892 MEDIUM 6.1 UPGRADE SemanticMediaWiki from 3.1.0 before 7.3.1 contains a reflected cross-site scripting vulnerability that allows
CVE-2026-116889 MEDIUM 6.1 UPGRADE SemanticMediaWiki from 2.5.0 before 7.3.1 contains a stored cross-site scripting vulnerability that allows use
CVE-2026-116888 MEDIUM 4.8 UPGRADE SemanticMediaWiki from 3.2.0 before 7.3.1 contains a stored cross-site scripting vulnerability that allows use
CVE-2026-116884 MEDIUM 6.1 UPGRADE SemanticMediaWiki from 5.0.0 before 7.3.1 contains a stored cross-site scripting vulnerability in ext.smw.tool
CVE-2026-116875 MEDIUM 6.1 UPGRADE SemanticMediaWiki from 3.0.0 before 7.3.1 contains a reflected cross-site scripting vulnerability in Special:A

References

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