Cyber Resilience

CVE-2026-40946

Critical

Published: 21 April 2026

Published
21 April 2026
Modified
22 April 2026
KEV Added
—
Patch
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CVSS Score v4 9.2 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0026 16.6th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-40946 is a critical-severity Improper Authentication (CWE-287) vulnerability. Its CVSS base score is 9.2 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked at the 16.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability details

Oxia is a metadata store and coordination system. Prior to 0.16.2, the OIDC authentication provider unconditionally sets SkipClientIDCheck: true in the go-oidc verifier configuration, disabling the standard audience (aud) claim validation at the library level. This allows tokens issued for…

more

unrelated services by the same OIDC issuer to be accepted by Oxia. This vulnerability is fixed in 0.16.2.

CWE(s)
CWE-287

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1550.001 Application Access Token Lateral Movement
Adversaries may use stolen application access tokens to bypass the typical authentication process and access restricted accounts, information, or services on remote systems.
attack.mitre.org →
Why these techniques?

OIDC audience validation bypass directly enables use of valid tokens issued to other applications (T1550.001) and unauthorized access via valid accounts (T1078).

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

Affected Assets

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-9 Previous Logon Notification
addresses: CWE-287

Detects unauthorized successful logons resulting from improper authentication implementations.

AT-1 Policy and Procedures
addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

AT-2 Literacy Training and Awareness
addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

AT-3 Role-based Training
addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

AU-10 Non-repudiation
addresses: CWE-287

Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.

AU-14 Session Audit
addresses: CWE-287

Session content review can reveal authentication bypasses or failures in session establishment.

AU-6 Audit Record Review, Analysis, and Reporting
addresses: CWE-287

Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.

CA-2 Control Assessments
addresses: CWE-287

Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.

References