# CVE-2026-116871: Semantic MediaWiki 3.0.0 before 7.3.1 Uncontrolled Recursion via Special:Ask

Status: published. Published: 2026-10-27. Updated: 2026-11-04.

Semantic MediaWiki 3.0.0 before 7.3.1 contains an uncontrolled recursion vulnerability in LegacyParser::getSubqueryDescription() that processes nested query tokens before depth limits apply. Unauthenticated attackers can submit deeply nested query elements to the action=ask API to consume substantial CPU and memory, tying up request workers.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/756492002752f937a9e115e14330b1181bd8c60c
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/e642f38c708dee7da5e885b8d40be8ffc56f3e87
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: disclosure@vulncheck.com) — https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/756492002752f937a9e115e14330b1181bd8c60c
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: disclosure@vulncheck.com) — https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/e642f38c708dee7da5e885b8d40be8ffc56f3e87

## Affected products and versions

- SemanticMediaWiki / SemanticMediaWiki: ≥ 3.0.0; < 7.3.1 (affected, semver); 7.3.1 (unaffected, semver). Source: CNA: VulnCheck

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:semantic-mediawiki:semantic_mediawiki:*:*:*:*:*:mediawiki:*:*",
            "versionEndExcluding": "7.3.1",
            "versionStartIncluding": "3.0.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 4.0: 8.7 (high); 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; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 8.7 (high); 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.39% as of 2026-11-04; percentile 32.92%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-674

## Exploit evidence

- exploit: https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (ADP: CISA-ADP)
- exploit: https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (disclosure@vulncheck.com)
- exploit: https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (134c704f-9b21-4f2e-91b3-4a467353bcc0)

## References

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (CNA: VulnCheck; vendor-advisory)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/756492002752f937a9e115e14330b1181bd8c60c (CNA: VulnCheck; patch)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/e642f38c708dee7da5e885b8d40be8ffc56f3e87 (CNA: VulnCheck; patch)

- https://www.vulncheck.com/advisories/semantic-mediawiki-3.0.0-before-7.3.1-uncontrolled-recursion-via-special-ask (CNA: VulnCheck; third-party-advisory)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (ADP: CISA-ADP; exploit)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/756492002752f937a9e115e14330b1181bd8c60c (disclosure@vulncheck.com; Patch)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/e642f38c708dee7da5e885b8d40be8ffc56f3e87 (disclosure@vulncheck.com; Patch)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (disclosure@vulncheck.com; Exploit, Vendor Advisory)

- https://www.vulncheck.com/advisories/semantic-mediawiki-3.0.0-before-7.3.1-uncontrolled-recursion-via-special-ask (disclosure@vulncheck.com; Third Party Advisory)

- https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-f8vw-wvm6-h2qq (134c704f-9b21-4f2e-91b3-4a467353bcc0; Exploit, Vendor Advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-116871; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116871; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116871; retrieved 2026-11-04; source updated Not reported

Revision: 8ca09ec5c7f635e41de05b3f8c9858b77756c7c80a248835edcd5a63c44f4c35

Canonical: https://y2.dev/cve/CVE-2026-116871

## Agent and API access

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- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

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