CVE-2026-40944 — oxia
CVE-2026-40944 is a CWE-295 vulnerability in github.com/oxia-db/oxia. A fix is available for github.com/oxia-db/oxia — see the affected versions and patch details below.
Oxia: TLS CA certificate chain validation fails with multi-certificate PEM bundles
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40944.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/oxia-db/oxiaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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 pem.Decode is ignored, so a corrupted CA file results in an empty certificate pool without any error.
Patches
Fixed by iterating over all PEM blocks in the file, parsing each CERTIFICATE block, and returning an error if no valid certificates are found.
Workarounds
Use CA files containing only a single certificate (the direct issuer of client certificates, not a chain).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/oxia-db/oxia | all versions | 0.16.2go get github.com/oxia-db/oxia@v0.16.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/oxia-db/oxia, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/oxia-db/oxia to 0.16.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40944 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40944 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-40944. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40944 in your dependencies?
O3 Security finds CVE-2026-40944 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.