Oxia's TLS CA certificate chain validation fails with multi-certificate PEM bundles

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.0 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U · score source

EPSS

• CVE-2026-40944: 0.16% estimated exploitation activity in the next 30 days; percentile 5.25 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The trustedCertPool() function in the TLS configuration only parses the first PEM block from CA certificate files. When a CA bundle contains multiple certificates (e.g., intermediate + root CA), only the first certificate is loaded. This silently breaks certificate chain validation for mTLS. Impact In deployments using mTLS with certificate chains (intermediate CA + root CA bundles), legitimate clients with properly chained certificates are rejected with x509: certificate signed by unknown authority. This degrades the security posture by making mTLS unusable with standard CA chain configurations, potentially forcing operators to disable client certificate verification. All versions using TLS with trustedCaFile configuration are affected. Details In common/security/tls.go, the trustedCertPool() method calls pem.Decode() only once, processing a single PEM block. The remaining bytes (containing additional certificates) are silently discarded. Additionally, the error return from…

Published by the source

14 Apr 2026, 23:15 UTC

Last modified by the source

24 Apr 2026, 20:39 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7jrq-q4pq-rhm6

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# Patch Next advisory brief: CVE-2026-40944

Advisory: Oxia's TLS CA certificate chain validation fails with multi-certificate PEM bundles
IDs: CVE-2026-40944, GHSA-7jrq-q4pq-rhm6
Record: https://patchnext.com/advisories/cve-2026-40944 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/oxia-db/oxia 0.16.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/oxia-db/oxia: affected <= 0.16.1; fixed in 0.16.2

## Suggested inspection (read-only)
- Go github.com/oxia-db/oxia: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/oxia-db/oxia.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7jrq-q4pq-rhm6 (GitHub-reviewed advisory GHSA-7jrq-q4pq-rhm6 lists affected ranges: Go github.com/oxia-db/oxia >=0 <=0.16.1)

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