Quick answers
- Is CVE-2026-116878 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-116878 being exploited in the wild.
- How severe is CVE-2026-116878?
- High severity, with a CVSS score of 7.5, published 27 October 2026.
- Which products and versions are affected?
- Semantic MediaWiki 2.5.0 to 7.3.0.
- Is there a fix for CVE-2026-116878?
- Yes: fixed in 7.3.1. Until then: Restrict access to Special:PropertyLabelSimilarity using MediaWiki permission controls or web server rules to prevent anonymous access to the vulnerable endpoint. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-116878 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-116878?
- Check whether you run Semantic MediaWiki at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 7.3.1
Restrict access to Special:PropertyLabelSimilarity using MediaWiki permission controls or web server rules to prevent anonymous access to the vulnerable endpoint.
Technical details
Semantic MediaWiki's Special:PropertyLabelSimilarity page accepts a caller-controlled limit parameter but fails to apply an SQL LIMIT when the value is zero or negative, causing the entire property table to be loaded into an O(n²) pairwise comparison algorithm using similar_text(). An unauthenticated attacker can repeatedly invoke this endpoint with limit=0 to force quadratic work proportional to the square of the number of user-defined properties, exhausting server resources. The fix enforces a bounded SQL LIMIT for all non-positive limit values.
Affected products
- Semantic MediaWiki Semantic MediaWiki 2.5.0 to 7.3.0
Timeline
- 2026-09-28: disclosed
- 2026-10-27: advisory