Cyber Resilience

CVE-2026-34093

Info Disclosure in Mediawiki ≤ 1.43.7

Published
11 May 2026
Modified
17 June 2026
Patch / advisory
CVSS Score v4 1.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/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:X/AU:X/R:A/V:X/RE:X/U:X
EPSS Score 0.0023 14th percentile
Risk Priority 15 floored blend · peak EPSS

Summary

CVE-2026-34093 is a low-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Mediawiki Mediawiki. Its CVSS base score is 1.1 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Domain Groups (T1069.002); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation MediaWiki. This vulnerability is associated with program files includes/Specials/SpecialUserRights.Php. This issue affects MediaWiki: from * before 1.43.7, 1.44.4, 1.45.2.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1069.002 Domain Groups Discovery
Adversaries may attempt to find domain-level groups and permission settings.
T1087.002 Domain Account Discovery
Adversaries may attempt to get a listing of domain accounts.
Why these techniques?

Direct unauthorized exposure of user rights/permissions data enables account and permission group discovery.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-34088Same product: Mediawiki Mediawiki
CVE-2026-58024Same product: Mediawiki Mediawiki
CVE-2026-34091Same product: Mediawiki Mediawiki
CVE-2023-29137Same product: Mediawiki Mediawiki
CVE-2026-34087Same product: Mediawiki Mediawiki
CVE-2024-40597Same product: Mediawiki Mediawiki
CVE-2025-61639Same product: Mediawiki Mediawiki
CVE-2026-58036Same product: Mediawiki Mediawiki
CVE-2026-58027Same product: Mediawiki Mediawiki
CVE-2026-58026Same product: Mediawiki Mediawiki

Affected Assets

mediawiki
mediawiki
≤ 1.43.7 · 1.44.0 — 1.44.4 · 1.45.0 — 1.45.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • AC-6 Least Privilege
  • AC-4 Information Flow Enforcement
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 7 hardening rules · 6 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V10.4.9
  • V11.7.1
  • V14.1.2
  • V14.2.4

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces authorization checks before allowing access to SpecialUserRights.php and the sensitive user rights data it exposes.

prevent

Ensures only users with explicit need-to-know privileges can view or alter user rights, limiting exposure of sensitive account information.

prevent

Controls information flows involving user rights data so that it is not released to unauthorized actors through the affected special page.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

PR.AA-05 directly enforces least-privilege authorization that blocks most unauthorized disclosures, yet CWE-200 also arises from logging, error messages, and side-channel paths that access controls alone do not address.

PR.DS-10 mostly match
prevents

PR.DS-10 mostly prevents CWE-200 by directly eliminating unauthorized access to sensitive data-in-use, yet only partially addresses the weakness because CWE-200 spans many other exposure vectors outside runtime protection.

PR.IR-01 mostly match
prevents

PR.IR-01's segmentation/zero-trust controls largely eliminate network-level unauthorized access paths that enable exposure, yet CWE-200 spans many additional vectors (API responses, logs, app logic) that network controls alone cannot close.

PR.PS-06 mostly match
prevents

Secure SDLC practices catch most exposure flaws via design, testing and release controls, yet CWE-200 spans runtime/config issues a single development outcome cannot fully close.

PR.AA-01 partial match
prevents

PR.AA-01 supplies proper credential lifecycle controls that reduce unauthorized access paths, yet leaves many other exposure vectors (error messages, logging, side channels, etc.) unaddressed.

PR.AA-03 partial match
prevents

Authentication verifies actor identity and is a prerequisite for access decisions, yet addresses only one facet of the broad set of exposure vectors in CWE-200.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Restricting anonymous or unknown access and encrypting high-value information limits the exposure of sensitive data that would otherwise be obtainable by unauthorized actors.

prevents

Suppressing system details, error specifics, and previous log-on information until successful authentication reduces the information an unauthenticated attacker can gather.

prevents

By requiring owners to assign sensitivity labels and corresponding handling rules, the control ensures that information is not left unmarked and therefore reduces the chance that sensitive data will be exposed to unauthorized actors.

prevents

Requiring encryption, access controls, and recipient authentication for transfers directly reduces the chance that sensitive data reaches an unauthorized observer.

prevents

Secure delivery, protected storage, and confidentiality of allocation records limit exposure of authentication material to unauthorized observers.

prevents

Requiring defined procedures, assigned roles, and technical/organizational measures for handling PII reduces the chance that sensitive personal data will be exposed to unauthorized actors through inadequate handling or missing safeguards.

References