CVE-2026-126565: Semantic MediaWiki 3.0.0 before 7.4.1 DoS via Exponential Concept Expansion
Semantic MediaWiki 3.0.0 before 7.4.1 contains a denial of service vulnerability in the ElasticStore and SPARQLStore ConceptDescriptionInterpreter classes, which re-expand concepts without memoization or an expansion budget. Users with page-edit rights can build acyclic chains of Concept: pages that fan out, so queries via concept page views, Special:Ask, or api.php action=ask exhaust CPU and memory.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue?
An attacker needs page-edit rights in the affected Semantic MediaWiki instance. They can create acyclic chains of Concept: pages with fan-out that causes exponential expansion.
Which components and request paths are affected?
The issue affects the ElasticStore and SPARQLStore ConceptDescriptionInterpreter classes. It can be triggered through concept page views, Special:Ask, or api.php requests using action=ask.
What is the impact of successful exploitation?
Concept expansion can exhaust CPU and memory, resulting in a denial of service. The provided data does not indicate confidentiality or integrity impact.
What version resolves the issue?
Upgrade to Semantic MediaWiki 7.4.1 or later. Versions from 3.0.0 before 7.4.1 are affected.