# CVE-2026-116871: Semantic MediaWiki uncontrolled recursion in query parser

Source: https://junglewise.ai/threats/cve-2026-116871-semantic-mediawiki-3-0-0-before-7-3-1-contains-an-uncontrolled  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-27. Updated: 2026-10-27  
License: CC BY 4.0 with a link back

CVE-2026-116871 · Severity: high · CVSS 7.5 · Published 2026-10-27

Semantic MediaWiki is a semantic search extension used in wikis to run complex queries over structured data. An attacker can submit deeply nested query parameters to the action=ask API endpoint without authentication, causing the parser to recurse excessively and consume CPU and memory resources, potentially denying service to legitimate users.

Technologies: [SemanticMediaWiki Semantic MediaWiki](https://junglewise.ai/threats/technologies/semanticmediawiki-semantic-mediawiki). Vendors: [SemanticMediaWiki](https://junglewise.ai/threats/vendors/semanticmediawiki).

## Quick answers

**Is CVE-2026-116871 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116871 being exploited in the wild.

**How severe is CVE-2026-116871?** High severity, with a CVSS score of 7.5, published 27 October 2026.

**Which products and versions are affected?** SemanticMediaWiki Semantic MediaWiki 3.0.0 before 7.3.1.

**Is there a fix for CVE-2026-116871?** Yes: fixed in 7.3.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116871 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-116871?** Check whether you run SemanticMediaWiki 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

## Technical details

The LegacyParser::getSubqueryDescription() function in Semantic MediaWiki processes nested query tokens recursively without enforcing depth limits before descending, allowing an attacker to trigger stack exhaustion via the action=ask API. An unauthenticated network attacker can craft malicious query parameters with excessive nesting depth to exhaust server resources. The fix enforces query depth validation before recursion rather than only pruning the finished tree.

## Affected products

- SemanticMediaWiki Semantic MediaWiki 3.0.0 before 7.3.1

## Timeline

- 2026-10-27: disclosed

## References

- [https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/756492002752f937a9e115e14330b1181bd8c60c](https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/756492002752f937a9e115e14330b1181bd8c60c)
- [https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/e642f38c708dee7da5e885b8d40be8ffc56f3e87](https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/e642f38c708dee7da5e885b8d40be8ffc56f3e87)

## Related threats

- [Semantic MediaWiki stored XSS in Special:Ask with ElasticStore](https://junglewise.ai/threats/cve-2026-126567-semantic-mediawiki-3-0-0-before-7-4-1-contains-a-stored-cross)
- [Semantic MediaWiki reflected XSS in TimeValueFormatter](https://junglewise.ai/threats/cve-2026-126563-semantic-mediawiki-2-4-0-before-7-4-1-contains-a-reflected-cross)
- [Semantic MediaWiki missing authorization in smwtask API](https://junglewise.ai/threats/cve-2026-116890-semantic-mediawiki-from-3-0-0-before-7-3-0-contains-a-missing)