CVE-2026-25651
MEDIUMCVE-2026-25651 is a medium-severity (CVSS 6.1) Open Redirect vulnerability in client-certificate-auth. O3 Security confirms whether CVE-2026-25651 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
client-certificate-auth has an Open Redirect via Host Header Injection in HTTP-to-HTTPS redirect
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
client-certificate-authnpmDescription
client-certificate-auth is middleware for Node.js implementing client SSL certificate authentication/authorization. Versions 0.2.1 and 0.3.0 of client-certificate-auth contain an open redirect vulnerability. The middleware unconditionally redirects HTTP requests to HTTPS using the unvalidated Host header, allowing an attacker to redirect users to arbitrary domains. This vulnerability is fixed in 1.0.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | client-certificate-auth | ≥ 0.2.1&&< 1.0.0 | 1.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for client-certificate-auth. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update client-certificate-auth to 1.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25651 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 pinpoints whether CVE-2026-25651 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-25651. 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-2026-25651 in your dependencies?
O3 detects CVE-2026-25651 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.