---
title: "CVE-2026-40946: Oxia has an OIDC token audience validation bypass via SkipClientIDCheck"
url: https://erroneo.us/security/cve/CVE-2026-40946/
description: "CVE-2026-40946 (github.com/oxia-db/oxia (Go)): Oxia is a metadata store and coordination system. Prior to 0.16.2, the OIDC authentication provider…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-21
date_modified: 2026-04-24
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-40946"
kev: false
cvss: 9.2
epss: 0.00408
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-40946: Oxia has an OIDC token audience validation bypass via SkipClientIDCheck

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 34: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 34% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/oxia-db/oxia (Go) <= 0.16.1, fixed in 0.16.2 . Check your lockfile, including transitive dependencies.

## What it is

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

## Affected packages

- Go `github.com/oxia-db/oxia` <= 0.16.1 → fixed: 0.16.2

## Affected products (CVE record)

- oxia-db oxia: < 0.16.2

## Severity

- GitHub_M CVSS 4.0: 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`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.41% probability of exploitation activity in the next 30 days; percentile 34.

## Sources

- [GitHub Advisory GHSA-fhvp-9hcj-6m33](https://github.com/advisories/GHSA-fhvp-9hcj-6m33)
- [CVE.org record CVE-2026-40946](https://www.cve.org/CVERecord?id=CVE-2026-40946)
- [NVD entry CVE-2026-40946](https://nvd.nist.gov/vuln/detail/CVE-2026-40946)
- [github.com](https://github.com/oxia-db/oxia/security/advisories/GHSA-fhvp-9hcj-6m33)

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Source page: https://erroneo.us/security/cve/CVE-2026-40946/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt