Open Redirect Affecting client-certificate-auth package, versions >=0.2.1 <1.0.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-CLIENTCERTIFICATEAUTH-15248346
- published8 Feb 2026
- disclosed6 Feb 2026
- creditUnknown
Introduced: 6 Feb 2026
CVE-2026-25651 (opens in a new tab)How to fix?
Upgrade client-certificate-auth to version 1.0.0 or higher.
Overview
client-certificate-auth is an Express/Connect middleware for mTLS client certificate authentication with reverse proxy support (AWS ALB, Envoy, Cloudflare, Traefik)
Affected versions of this package are vulnerable to Open Redirect via the redirect process. An attacker can cause users to be redirected to arbitrary domains by injecting a malicious Host header in HTTP requests. This can lead to phishing, credential theft, referer leakage, or cache poisoning. This is only exploitable if HTTP traffic reaches the application without TLS termination setting x-forwarded-proto: https.
Workaround
This vulnerability can be mitigated by blocking HTTP traffic at the network or load balancer level, ensuring the reverse proxy always sets x-forwarded-proto: https, or adding middleware to validate the Host header against an allowlist before processing.