10.0 CVSS RCE via OS command injection in a widely deployed MediaWiki extension; enables full server compromise of internal/external wiki instances and warrants broad notification.
CVE-2026-100382
RCE via OS command injection in MediaWiki ExternalData extension (<3.7).
Is CVE-2026-100382 being exploited?
Not confirmed. CVE-2026-100382 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 1.2% probability of exploitation in the next 30 days.
How severe is CVE-2026-100382?
CVE-2026-100382 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-100382?
Yes. A fix has been recorded for CVE-2026-100382. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-100382 affect?
CVE-2026-100382 affects MediaWiki ExternalData extension < 3.7, MediaWiki instances using ExternalData extension. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-100382?
Upgrade ExternalData to >=3.7 or remove/disable it; audit and isolate affected hosts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution on wiki servers via ExternalData input, enabling full system compromise and data exfiltration.
Immediate action required
- affected< 3.7
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
public exploits
Unvetted proof-of-concept code on GitHub: 1 GitHub proof of concept
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- none
- automatable
- yes
- technical impact
- total
Assessed by CISA 26 Sept 2026 (SSVC 2.0.3).
timeline
- 25 Sept 2026Published
- 26 Sept 2026CISA SSVC assessment: exploitation none · 1 day later
- 26 Sept 2026CVE record last updated · same day later
- 27 Sept 2026First proof-of-concept repository on GitHub (unvetted) · same day later
- 27 Sept 2026Analysed by vulneraibility.com · same day later
- Linkphabricator.wikimedia.org /T434961
- Linkgerrit.wikimedia.org /r/c/mediawiki/extensions/ExternalData/+/1326012
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.