9router: Login brute-force protection bypass via spoofed X-Forwarded-For header

Exploitation

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

CVSS

7.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS

• CVE-2026-55501: 0.38% estimated exploitation activity in the next 30 days; percentile 31.94 (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 9router dashboard login rate limiter derives the client identity from the attacker-controlled X-Forwarded-For HTTP header. When 9router is directly exposed, or deployed behind a reverse proxy that does not overwrite untrusted forwarding headers, a remote attacker can rotate the X-Forwarded-For value on each login attempt and receive a fresh rate-limit bucket every time. This bypasses the dashboard brute-force protection and makes the login lockout mechanism ineffective. Details | Component | File | Note | | ---------------------------- | --------------------------------- | --------------------------------------------------------------------------- | | Dashboard login rate limiter | src/lib/auth/loginLimiter.js | Uses X-Forwarded-For as the client identity without a trusted-proxy check | | Dashboard login route | src/app/api/auth/login/route.js | Calls checkLock() and recordFail() using the spoofable client identity | Vulnerable Code src/lib/auth/loginLimiter.js: The…

Published by the source

6 Jul 2026, 21:46 UTC

Last modified by the source

6 Jul 2026, 22:11 UTC

Source last checked

26 Oct 2026, 12:56 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7cfm-pqrj-xgq7

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7cfm-pqrj-xgq7

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# Patch Next advisory brief: CVE-2026-55501

Advisory: 9router: Login brute-force protection bypass via spoofed X-Forwarded-For header
IDs: CVE-2026-55501, GHSA-7cfm-pqrj-xgq7
Record: https://patchnext.com/advisories/cve-2026-55501 (revision 2, source checked 26 Oct 2026, 12:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: 9router 0.4.77. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm 9router: affected <= 0.4.71; fixed in 0.4.77

## Suggested inspection (read-only)
- `npm ls 9router --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## 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 9router.
- 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://osv.dev/vulnerability/GHSA-7cfm-pqrj-xgq7 (OSV record GHSA-7cfm-pqrj-xgq7 lists affected ranges: npm 9router >=0 <0.4.77 (fixed))
- Verified: https://github.com/advisories/GHSA-7cfm-pqrj-xgq7 (GitHub-reviewed advisory GHSA-7cfm-pqrj-xgq7 lists affected ranges: npm 9router >=0 <=0.4.71)

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