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-2026-126565
MEDIUMPre-NVD 4.34.3ElevatedEG-KEV Tier 3: ElevatedEG-KEV is EchelonGraph's own tiering of exploitation signals from CISA KEV, CISA's SSVC data (Vulnrichment), ransomware data, public exploit-code references and EPSS.Tier 3 is not evidence of exploitation. It means public exploit code is referenced, or CISA's SSVC data says "public PoC", or EPSS ranks the CVE in the top 5%.Signals for this CVE: CISA's SSVC exploitation value: public PoC.EchelonGraph confidence 38%: a heuristic from the tier and the number of signals, not a measured probability.
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 4.3 from GitHub Security Advisory (severity: MODERATE) published 2026-11-11. A secondary CVSS source baseline 4.3; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Also known asEUVD-2026-123080 (ENISA EUVD) · GHSA-vpc6-m642-jj3j (GitHub Security Advisories)Source: ENISA EUVD
4.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 4.3Exploit: No code on recordExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 4.3
- EG Score
- 4.3MEDIUMhigh confidence
- EG Risk
- 35EG Risk 35/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity43% × 45%Impact severity (EG Severity): CVSS 4.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.4%
- EPSS %ILE
- 32nd
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (4.3): severity, escalated by confirmed exploitation. This CVE's 4.3 is its impact severity (EG Severity), not escalated.
- EG Severity
- 4.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
November 11, 2026
Last Modified
November 12, 2026
Advisory Details (6)
Auto-updated Nov 11, 2026🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
Web page
Semantic MediaWiki 3.0.0 before 7.4.1 DoS via Exponential Concept Expansion | Advisories | VulnCheck
https://www.vulncheck.com/advisories/semantic-mediawiki-3.0.0-before-7.4.1-dos-via-exponential-concept-expansionGitHub advisoryMentions a patch (unverified)🟡 PoC Available
Denial of service: concept expansion in the ElasticStore and SPARQLStore query engines is not memoized or bounded, so an acyclic concept fan-out makes query building grow about sixfold per level · Advisory · SemanticMediaWiki/SemanticMediaWiki · GitHub
Affected: 7.4.1) is tracked separately as
https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-24v2-mf3g-84chGitHub release Patch Available
SMW 7.4.1
Patch available: SemanticMediaWiki/SemanticMediaWiki 7.4.1
https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.4.1GitHub commit Patch Available
commit 86ce13254ffd (SemanticMediaWiki/SemanticMediaWiki)
Patch available: SemanticMediaWiki/SemanticMediaWiki 7.4.1 (contains commit 86ce13254ffd)
https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/86ce13254ffd91406ef43ea403ae072a7e3a38b3Web page
SemanticMediaWiki/src/SPARQLStore/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php at 7.4.0 · SemanticMediaWiki/SemanticMediaWiki · GitHub
https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/SPARQLStore/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php#L49-L105Web page
SemanticMediaWiki/src/Elastic/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php at 7.4.0 · SemanticMediaWiki/SemanticMediaWiki · GitHub
https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/Elastic/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php#L34-L75Vendor Advisories for CVE-2026-126565(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
- 2026-11-12 21:08 UTCGHSA enrichmentGHSA-vpc6-m642-jj3j · GitHub severity MODERATE · GitHub CVSS 4.3
- 2026-11-12 20:30 UTCEchelonGraph re-scored
- 2026-11-12 20:30 UTCGHSA enrichmentGHSA-vpc6-m642-jj3j · GitHub severity MODERATE · GitHub CVSS 4.3
- 2026-11-12 19:42 UTCEchelonGraph re-scored
- 2026-11-12 19:42 UTCGHSA enrichmentGHSA-vpc6-m642-jj3j · GitHub severity MODERATE · GitHub CVSS 4.3
- 2026-11-12 19:22 UTCEchelonGraph re-scored
- 2026-11-12 19:22 UTCGHSA enrichmentGHSA-vpc6-m642-jj3j · GitHub severity MODERATE · GitHub CVSS 4.3
- 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-11-11 08:17 UTCEchelonGraph re-scored
- 2026-11-11 08:17 UTCGHSA enrichmentGHSA-vpc6-m642-jj3j · GitHub severity MODERATE · GitHub CVSS 4.3
- 2026-11-11 03:28 UTCEchelonGraph re-scored
- 2026-11-11 03:00 UTCENISA EUVD ID recordedEUVD-2026-123080 · Source: ENISA EUVD
- 2026-11-11 02:44 UTCEchelonGraph re-scoredFirst assessed: 4.3 MEDIUM
- 2026-11-11 02:44 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-126565?
CVE-2026-126565 is a medium-severity vulnerability; its CVE record was published on November 11, 2026. 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…
When was CVE-2026-126565 made public?
CVE-2026-126565 was made public on November 10, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on November 11, 2026. EchelonGraph's copy of the record carries a last-modified date of November 12, 2026; the record at its source may have been updated since.
Is CVE-2026-126565 actively exploited?
CVE-2026-126565 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (32nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-126565?
CVE-2026-126565 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-126565?
A fix for CVE-2026-126565 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-126565 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
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