CVE-2026-55501
HIGH9router: Login brute-force protection bypass via spoofed X-Forwarded-For header
Blast Radius
9routerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
9Router is an AI router & token saver. Prior to 0.4.80, the dashboard login rate limiter in src/lib/auth/loginLimiter.js derives the client identity from the attacker-controlled X-Forwarded-For HTTP header, and src/app/api/auth/login/route.js uses that spoofable value for checkLock and recordFail. A remote attacker can rotate the X-Forwarded-For value on each login attempt to receive a fresh rate-limit bucket, bypass the 5-attempt threshold and progressive lockout durations, and perform unlimited brute-force attempts against the dashboard password. This issue is fixed in version 0.4.80.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | 9router | all versions | 0.4.77 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for 9router. 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 9router to 0.4.77 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55501 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-2026-55501 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-2026-55501. 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-2026-55501 in your dependencies?
O3 detects CVE-2026-55501 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.