Vulnerability report

Exploited in the wild High confidence Not in CISA KEV

CVE-2026-100382

Unauthenticated remote code execution through wikitext in ExternalData

Wikimedia / Mediawiki - ExternalData Extension · affected before 3.7

View live feed Monitor via API Watch CVE-2026-100382
Severity
CVSS 10.0 · Critical
Confidence
High
Exploit status
Exploited in the wild
EPSS
0.9%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-100382 is an unauthenticated Unauthenticated remote code execution through wikitext in ExternalData affecting Wikimedia Mediawiki - ExternalData Extension. Improper Neutralization of Special Elements used in...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is high. Also confirmed by third-party sources.

Who is affected?

Wikimedia / Mediawiki - ExternalData Extension affected before 3.7.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Unauthenticated remote code execution through wikitext in ExternalData

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability in Wikimedia Foundation Mediawiki - ExternalData Extension allows OS Command Injection.

This issue affects Mediawiki - ExternalData Extension: from * before 3.7.

Wikimedia Foundation Affected
Mediawiki - ExternalData Extension
Before 3.7
Published
25 Sep 2026
Exploitation Reported
01 Oct 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Wikimedia

Recorded 01 Oct 2026

A trusted third party reported exploitation.

Proof of concept available

GitHub

Recorded 27 Sep 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
Wikimedia First 2026-10-01 09:43 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

10.0 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

EPSS

0.9%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE-78

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

nth347/mediawiki-CVE-2026-100382

github · Created 2026-09-27 15:31:44 UTC · 0 stars · AI assessment 90%

Timeline

From disclosure to observed exploitation

  1. 09:43 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  2. 02:20 UTC

    Added to the Previdian watchlist

    Pro and Enterprise Watch users had 3 days of early warning before Previdian confirmed it as a KEV.

  3. 15:31 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 21:04 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 19:28 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-100382

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-100382",
  "confidence": "High",
  "cvss_score": 10.0,
  "cvss_estimated": false,
  "epss_score": 0.00947,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}