Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-126566 Overview
Semantic MediaWiki 7.3.1 before 7.4.1 contains an incorrect authorization vulnerability in EditProtectionUpdater::userMayChangeProtection() that checks protection changes against the page's latest revision author. Editors can add {{#set:Is edit protected=false}} to a transcluded template, removing administrator edit and move protection logged under the administrator's name.
Critical Impact
Affected Products
- Semantic MediaWiki: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-11: CVE-2026-126566 published to the National Vulnerability Database by disclosure@vulncheck.com
- 2026-11-11: last updated in the NVD database
Technical Details for CVE-2026-126566
Vulnerability Analysis
CVE-2026-126566 is a Incorrect Authorization weakness (CWE-863: Incorrect Authorization) in Semantic MediaWiki. Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. The permission check exists but gets the answer wrong.
With a CVSS base score of 7.1, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The weakness is classified as CWE-863: Incorrect Authorization. The permission check exists but gets the answer wrong.
Attack Vector
Based on the CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Detection Methods for CVE-2026-126566
Detection Strategies
- Inventory every instance of Semantic MediaWiki and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward Semantic MediaWiki application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-126566
Immediate Actions Required
- Apply the fixed version of Semantic MediaWiki named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for Semantic MediaWiki.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
- CWE-863: Incorrect Authorization More CVEs with this weakness
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
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