CVE-2026-34090
📛 CVE Title
Suggested investigations: Handle suppressed usernames
Description
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.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- wikimedia-foundation
- CVSS severity
- MEDIUM
- CVSS score
- 4.8 / 10
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/R:U- Effective score
- 4.8 / 10 MEDIUM source: CNA overview
- CWE(s)
-
CWE-200 - Reserved
- 2026-03-25
- Published
- 2026-05-11 16:50 UTC
- Last updated
- 2026-05-11 17:51 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34090.json
- Linked Threat
- CVE-2026-34090 — CVE-2026-34090
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-05-11 16:17:30 UTC
- NVD last modified
- 2026-05-14 16:42:57 UTC
- NVD CVSS v3.1
- 7.5 / 10 HIGH source: nvd@nist.gov
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Exploitability subscore
- 3.9 / 10
- Impact subscore
- 3.6 / 10
- EPSS score
- 0.0003 (probability of exploitation in next 30 days)
- EPSS percentile
- 10.43% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24
NVD / KEV / EPSS data refreshed 2026-05-25 12:38 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-29062 - Assigner
- wikimedia-foundation
- Published
- May 11, 2026, 2:50:50 PM
- Updated
- May 11, 2026, 3:51:32 PM
- EUVD base score (CVSS 4.0)
-
4.8 / 10
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/R:U - EUVD-reported EPSS
- 0.0400
- Vendors
- Wikimedia Foundation
- Products
-
CheckUser (1.45.0 <1.45.2)
ENISA description: 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.
EUVD references (1)
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Wikimedia Foundation | CheckUser |
1.45.0 (affected)
|
— |
Affected products — CPE 2.3 (1) NVD
NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.
cpe:2.3:a:mediawiki:checkuser:*:*:*:*:*:mediawiki:*:*
Vendor references (1)
References embedded in the original CVE record by the assigning CNA.
MITRE references (1) cveawg.mitre.org
Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.
Web references (3)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- https://nvd.nist.gov/vuln/detail/CVE-2026-34090 tenable:nvd.nist.gov
- https://www.cve.org/CVERecord?id=CVE-2026-34090 tenable:www.cve.org
- https://www.first.org/epss/ tenable:www.first.org
NVD-tagged references (1)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://phabricator.wikimedia.org/T411366 c4f26cc8-17ff-4c99-b5e2-38fc1793eacc Issue TrackingPatch
Remediations (18)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:cyberpress.org
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .
2026-05-23 21:01 UTC -
web:krebsonsecurity.com
Microsoft expects that exploitation is more likely. May's Patch Tuesday is a welcome respite from April, which saw Microsoft fix a near-record 167 security flaws.
2026-05-23 21:01 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-05-23 21:01 UTC -
web:windowsforum.com
Microsoft's April 2026 Patch Tuesday lands as one of the busiest security releases in recent memory, with 163 vulnerabilities closed across Windows, Office, SharePoint, .NET, Visual Studio, Dynamics 365, SQL Server, Azure, Defender Antimalware Platform, PowerShell, and related services. The...
2026-05-23 21:01 UTC -
web:www.bleepingcomputer.com
Today is Microsoft's May 2026 Patch Tuesday, with security updates for 120 flaws and no zero-days disclosed this month.
2026-05-23 21:01 UTC -
web:www.cisecurity.org
<p>Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for remote code execution. Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or ...
2026-05-23 21:01 UTC -
web:www.crowdstrike.com
Microsoft has released security updates for 130 vulnerabilities, including 30 critical, in its May 2026 Patch Tuesday rollout.
2026-05-23 21:01 UTC -
web:www.dbtsupport.com
The May 2026 Microsoft Patch Tuesday release includes security updates across supported Microsoft products and should be reviewed directly in the Microsoft Security Update Guide for the final CVE list, affected products, severity ratings, exploitability assessments, and any revised guidance.
2026-05-23 21:01 UTC -
web:www.oracle.com
This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.
2026-05-23 21:01 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-05-23 21:01 UTC -
web:thecyberexpress.com
Microsoft's Patch Tuesday April 2026 release has introduced one of the most extensive security update rollouts of the year, addressing a total of 167 vulnerabilities across Windows operating systems and associated software. This latest Microsoft Patch Tuesday also includes fixes for two zero-day ...
2026-05-26 02:51 UTC -
web:thehackernews.com
Microsoft patched 138 flaws, including 30 Critical bugs, as AI discovery expands Patch Tuesday risk.
2026-05-26 02:51 UTC -
web:threatprotect.qualys.com
Zero-day Vulnerabilities Patched in April Patch Tuesday Edition CVE - 2026 -33825: Microsoft Defender Elevation of Privilege Vulnerability Microsoft Defender is a comprehensive, AI-powered security suite that provides malware protection, phishing detection, and web protection for individuals and businesses.
2026-05-26 02:51 UTC -
web:vulert.com
Microsoft's May 2026 Patch Tuesday fixes 138 vulnerabilities, including critical Windows DNS and Netlogon RCE flaws. Learn the risks, key CVEs , mitigation steps, and how Vulert can help.
2026-05-26 02:51 UTC -
web:windowsreport.com
Microsoft has released its May 2026 Patch Tuesday updates for Windows 11 and Windows 10, shipping as KB5089549 and KB5087544. The updates include fixes for more than 130 security vulnerabilities across Windows, Office, SharePoint, DNS components, and core system services, as Bleeping Computer writes. While no publicly disclosed zero-day vulnerabilities were reported this month, the […]
2026-05-26 02:51 UTC -
web:www.bleepingcomputer.com
Today is Microsoft's April 2026 Patch Tuesday with security updates for 167 flaws, including 2 zero-day vulnerabilities.
2026-05-26 02:51 UTC -
web:www.lansweeper.com
Which vulnerabilities, issues, and other things did Microsoft update? Discover what's new using Lansweeper's Patch Tuesday May 2026 summary.
2026-05-26 02:51 UTC -
web:www.windowscentral.com
Windows 11 May 2026 update fails on some PCs, but Microsoft has already shipped a workaround, and it's working on a permanent fix .
2026-05-26 02:51 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-34090.json.
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