Semantic MediaWiki 3.0.0 before 7.4.1 DoS via Exponential Concept Expansion
- Exploited
- No known exploitation
- Fix
- Fixed in 7.4.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 7.4.1.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 8/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Semantic MediaWiki versions before 7.4.1 are affected by a denial-of-service bug in how concept queries are expanded. A remote attacker with low-privilege login (such as page-edit rights) can craft chains of Concept pages that make queries through concept views, Special:Ask, or the API exhaust server CPU and memory.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure3/25Reachable over the network · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity5.3/10CVSS 5.3
- No patch0/5No signal
What would change the score
- Would score about 63 if added to CISA KEV
- Would score about 58 if CISA's SSVC rates exploitation active
- Would score about 27 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 7.4.1.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126565 (Semantic MediaWiki 3.0.0 before 7.4.1 DoS via Exponential Concept Expansion), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-126565 (entry last updated 2026-11-11): Affected: - SemanticMediaWiki SemanticMediaWiki: from 3.0.0, fixed in 7.4.1 Fixed versions: 7.4.1. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-126565 is not listed as of cve.now's last read. This KEV status is for CVE-2026-126565 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-24v2-mf3g-84ch - https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/86ce13254ffd91406ef43ea403ae072a7e3a38b3 - https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.4.1 - https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/Elastic/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php#L34-L75 - https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/SPARQLStore/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php#L49-L105 - https://www.vulncheck.com/advisories/semantic-mediawiki-3.0.0-before-7.4.1-dos-via-exponential-concept-expansion Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-126565 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126565.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- SemanticMediaWiki SemanticMediaWiki
From 3.0.0 · fixed in 7.4.1
Evidence 8
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 5
- Patch
- Repository
- Repository
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126565
Is CVE-2026-126565 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-126565?
SemanticMediaWiki: from 3.0.0 before 7.4.1.Source: cve.now feed data
How do I fix CVE-2026-126565?
Upgrade to a fixed version: 7.4.1.Source: cve.now feed data