CVE-2026-116878: Semantic MediaWiki 2.5.0 before 7.3.1 Resource Exhaustion via Special:PropertyLabelSimilarity
Semantic MediaWiki from 2.5.0 before 7.3.1 contains an uncontrolled resource consumption vulnerability that allows anonymous attackers to force quadratic computation by supplying a zero limit to Special:PropertyLabelSimilarity. Attackers can send repeated requests with limit=0 to bypass the SQL LIMIT and trigger pairwise similartext() comparisons, exhausting PHP CPU, memory, and database connections.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to exploitation?
Semantic MediaWiki versions from 2.5.0 through versions before 7.3.1 are affected. The vulnerable endpoint is Special:PropertyLabelSimilarity.
Does exploitation require an account or user interaction?
No. The vulnerability can be exploited anonymously and does not require user interaction; an attacker can submit requests with a zero limit value.
What is the likely operational impact of an attack?
Repeated limit=0 requests can bypass the SQL LIMIT and trigger quadratic pairwise similar_text() comparisons. This can exhaust PHP CPU and memory as well as database connections, causing availability impact.