CVE-2026-5266Network attack vector

Notification disclosure via missing OAuth grant check

Published May 11, 2026 · Updated May 11, 2026

Information disclosure in Wikimedia Foundation Echo before 1.43.7, 1.44.4, or 1.45.2 allows remote authenticated users to read notifications. ApiEchoNotifications authorizes the logged-in user but does not require an OAuth grant dedicated to notification access, so any OAuth consumer can request that user's private notifications. Exploitation requires a user to authorize an OAuth tool, and the consequence is limited to disclosure of that user's Echo notification data.

CVSS severity2.3
Low
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Wikimedia Foundation Echo before 1.43.7, 1.44.4, or 1.45.2 allows remote authenticated users to read notifications. ApiEchoNotifications authorizes the logged-in user but does not require an OAuth grant dedicated to notification access, so any OAuth consumer can request that user's private notifications. Exploitation requires a user to authorize an OAuth tool, and the consequence is limited to disclosure of that user's Echo notification data.

The record

CVE
CVE-2026-5266
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Wikimedia Foundation
Product
Echo
Classifications
CWE-200, T1550.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=* <1.43.7, 1.44.4, 1.45.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Wikimedia Foundation · Echoversion=* <1.43.7, 1.44.4, 1.45.2

Published CVSS scores

2.3Wikimedia FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1550.001Use Alternate Authentication Material: Application Access Token

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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