CVE-2026-0817Network attack vector

Unauthenticated meeting and chat URL disclosure

Published Jan 9, 2026 · Updated Jan 9, 2026

Missing authorization in MediaWiki CampaignEvents 1.39, 1.43, 1.44, and 1.45 allows remote attackers to read meeting and chat URLs. GetEventRegistrationHandler returns meeting and chat URL fields from GET campaignevents/v0/event_registration/{id} without checking registration eligibility or blocks. Network access and a valid event registration ID are sufficient; the flaw discloses joining links but does not alter events or registrations.

CVSS severity5.3
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in MediaWiki CampaignEvents 1.39, 1.43, 1.44, and 1.45 allows remote attackers to read meeting and chat URLs. GetEventRegistrationHandler returns meeting and chat URL fields from GET campaignevents/v0/event_registration/{id} without checking registration eligibility or blocks. Network access and a valid event registration ID are sufficient; the flaw discloses joining links but does not alter events or registrations.

The record

CVE
CVE-2026-0817
Published
Jan 9, 2026
Updated
Jan 9, 2026
Vendor
Wikimedia Foundation
Product
MediaWiki CampaignEvents
Classifications
CWE-862, CAPEC-122, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.39
  2. Affected versionversion=1.43
  3. Affected versionversion=1.44
  4. Affected versionversion=1.45

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wikimedia Foundation · MediaWiki CampaignEventsversion=1.39; version=1.43; version=1.44; version=1.45

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
CAPEC-122Privilege Abuse
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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