CVE-2026-34087: Users API leaks whether privileged users have their user groups disabled for lack of 2FA

Q: What is the severity of CVE-2026-34087?

CVE-2026-34087 has a medium severity level due to the potential exposure of sensitive information.

Q: How do I fix CVE-2026-34087?

To fix CVE-2026-34087, upgrade Wikimedia Foundation OATHAuth to version 1.43.7 or later, and ensure that your MediaWiki installation is updated past version 1.45.2.

Q: What is the impact of CVE-2026-34087?

CVE-2026-34087 allows unauthorized users to determine whether privileged users have their user groups disabled due to a lack of two-factor authentication.

Q: Which versions are affected by CVE-2026-34087?

CVE-2026-34087 affects Wikimedia Foundation OATHAuth versions prior to 1.43.7, 1.44.4, and 1.45.2.

Q: Who is impacted by CVE-2026-34087?

Users of Wikimedia Foundation OATHAuth and MediaWiki versions specified in CVE-2026-34087 are at risk.

Published May 11, 2026

Updated

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation OATHAuth. This issue affects OATHAuth: from * before 1.43.7, 1.44.4, 1.45.2.

Affected Software

4 affected components

Wikimedia Foundation OATHAuth<1.43.7, =1.44.4, =1.45.2

MediaWiki MediaWiki<1.43.7

MediaWiki MediaWiki>=1.44.0<1.44.4

MediaWiki MediaWiki>=1.45.0<1.45.2

Event History

May 11, 2026

CVE Published

via MITRE·02:40 PM

Data Sourced

via MITRE·02:40 PM

DescriptionWeakness

Data Sourced

via NVD·04:17 PM

DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

What is the severity of CVE-2026-34087?

CVE-2026-34087 has a medium severity level due to the potential exposure of sensitive information.

How do I fix CVE-2026-34087?

To fix CVE-2026-34087, upgrade Wikimedia Foundation OATHAuth to version 1.43.7 or later, and ensure that your MediaWiki installation is updated past version 1.45.2.

What is the impact of CVE-2026-34087?

CVE-2026-34087 allows unauthorized users to determine whether privileged users have their user groups disabled due to a lack of two-factor authentication.

Which versions are affected by CVE-2026-34087?

CVE-2026-34087 affects Wikimedia Foundation OATHAuth versions prior to 1.43.7, 1.44.4, and 1.45.2.

Who is impacted by CVE-2026-34087?

Users of Wikimedia Foundation OATHAuth and MediaWiki versions specified in CVE-2026-34087 are at risk.

CVSS Score

5.1Medium

Medium Severity

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:N/VA:N/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:N/AU:Y/R:A/V:X/RE:M/U:X

Security Metrics

Risk Score43

Severitymedium(5.1)

CWE

200

Timeline

PublishedMay 11, 2026

Updated

References

phabricator.wikimedia.org/T412061

Company

Resources

Contact

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