Summary
Oxia has an OIDC token audience validation bypass via SkipClientIDCheck
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 unrelated services by the same OIDC issuer to be accepted by Oxia.
Details
In oxiad/common/rpc/auth/oidc.go, both createStaticKeyVerifier() and createRemoteVerifier() set SkipClientIDCheck: true. While a custom audience check exists in Authenticate(), the library-level check, which validates the aud claim against the expected client_id, is completely bypassed.
Workarounds
Ensure network-level isolation so that only trusted services can reach the Oxia gRPC endpoints.
Impact
In deployments using OIDC authentication, an attacker possessing a valid JWT token issued by the same identity provider but intended for a different service (different client_id/aud) can authenticate to Oxia. This bypasses the intended audience isolation of OAuth2/OIDC.
All versions using OIDC authentication are affected.
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed by removing SkipClientIDCheck: true and setting the ClientID field from the configured AllowedAudiences.
Frequently Asked Questions
- What is CVE-2026-40946? CVE-2026-40946 is a critical-severity improper authentication vulnerability in github.com/oxia-db/oxia (go), affecting versions <= 0.16.1. It is fixed in 0.16.2. The application does not adequately verify the identity of a user, device, or process before granting access.
- Which versions of github.com/oxia-db/oxia are affected by CVE-2026-40946? github.com/oxia-db/oxia (go) versions <= 0.16.1 is affected.
- Is there a fix for CVE-2026-40946? Yes. CVE-2026-40946 is fixed in 0.16.2. Upgrade to this version or later.
- Is CVE-2026-40946 exploitable, and should I be worried? Whether CVE-2026-40946 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-40946 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-40946? Upgrade
github.com/oxia-db/oxiato 0.16.2 or later.