Semantic MediaWiki: Stored cross-site scripting in Special:Browse factbox
Summary
Semantic MediaWiki 2.5.0 up to 7.4.0 contains a stored cross-site scripting vulnerability in the formatting of property labels on Special:Browse and the smwbrowse API. A user with page-edit rights can set a preferred property label containing malicious HTML that runs in the browser of anyone who views the page, including administrators. Successful exploitation can allow actions in the context of the victim's session, such as reading or changing wiki content.
Affected
- Semantic MediaWiki 2.5.0 to before 7.4.1 (Packagist: SemanticMediaWiki)
Fixed in
- Upgrade to Semantic MediaWiki 7.4.1 or later
Workaround
- Unknown. No vendor workaround identified; upgrading is the reliable fix.
- Limit page-edit rights to trusted users until the upgrade is done.
Exploitation
- No known exploitation at the time of writing.
- No public exploit code confirmed.
- Not listed in the CISA KEV catalog.
Our recommendation
- Upgrade Semantic MediaWiki to 7.4.1 in the next maintenance window; back up the wiki and database first, as the release includes database changes.
- Upgrade the other Semantic MediaWiki CVEs fixed in the same release (CVE-2026-126559 to CVE-2026-126567) at the same time.
- Review who holds page-edit rights and remove unnecessary accounts.
- Check existing property labels for unexpected HTML or script content.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Vendor advisory GHSA-mc5x-2j7v-x8hp github.com
- Release 7.4.1 github.com
- Fix commit c9bf9f2 github.com
- VulnCheck advisory www.vulncheck.com
- Vulnerable code ValueFormatter.php at 7.4.0 github.com
- Extension:Semantic MediaWiki www.mediawiki.org
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 19:03.
Original description (NVD)
Semantic MediaWiki 2.5.0 before 7.4.1 contains a stored cross-site scripting vulnerability in ValueFormatter::getFormattedSubject() that renders property label segments after a literal as unescaped markup. Users with page-edit rights can set a preferred property label containing an img onerror payload that executes when anyone, including administrators, views Special:Browse or the smwbrowse API.
NVD references (5)
- https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/MediaWiki/Specials/Browse/ValueFormatte…
- https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/c9bf9f25549bb2f5eab916339b267a1732002c4c
- https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.4.1
- https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-mc5x-2j7v-x8hp
- https://www.vulncheck.com/advisories/semantic-mediawiki-2.5.0-before-7.4.1-stored-xss-via-special-browse-fact…
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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