CVE-2026-34090

HIGHNVD 7.57.5—

7.5

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation CheckUser.

This issue affects CheckUser: from 1.45.0 before 1.45.2.

CVSS v3: 7.5
EG Score: 7.5(high)
EPSS: 10.6%
KEV: Not listed

Published

May 11, 2026

Last Modified

May 14, 2026

Advisory Details (1)

Auto-updated May 14, 2026

No patch confirmed yet.

generic

⚓ T411366 CVE-2026-34090: Suggested investigations: Handle suppressed usernames

https://phabricator.wikimedia.org/T411366

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Data Freshness Timeline

(refreshed 16× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-31 22:30 UTCepss_batch
2026-05-31 22:30 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-29 13:44 UTCepss_batch
2026-05-29 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-26 13:44 UTCepss_batch
2026-05-26 07:18 UTCepss_batch
2026-05-26 07:18 UTCepss_batch
2026-05-20 22:38 UTCepss_batch
2026-05-20 22:38 UTCepss_batch
2026-05-20 13:19 UTCEG score recompute
2026-05-20 13:18 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-34090?

CVE-2026-34090 is a high vulnerability published on May 11, 2026. Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation CheckUser. This issue affects CheckUser: from 1.45.0 before 1.45.2.

When was CVE-2026-34090 disclosed?

CVE-2026-34090 was first published in the National Vulnerability Database on May 11, 2026, with the most recent update on May 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-34090 actively exploited?

CVE-2026-34090 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 10.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-34090?

CVE-2026-34090 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2026-34090?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-34090, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2026-34090

📅 Published

🔄 Last Modified

📋 Advisory Details (1)

⚓ T411366 CVE-2026-34090: Suggested investigations: Handle suppressed usernames

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2026-34090?

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Advisory Details (1)

Frequently asked(5)

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