CVE-2026-55638 json
9router: Unauthenticated LLM proxy access via /codex rewrite authorization bypass
published 2026-07-10 4 mo ago modified 2026-10-25 15 d ago also GHSA-8gmq-j984-vp4r , EUVD-2026-42931
- cvss
- 8.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 6.6%
- EPSS 6.6% chance of exploitation in 30 days, percentile 93%
- public exploits
- 0
- none known
Summary
9Router is an AI router & token saver. Prior to 0.5.2, 9router protects /v1, /v1beta, /api/v1, and /api/v1beta in src/dashboardGuard.js but omits /codex before next.config.mjs rewrites /codex/* to /api/v1/responses. A remote unauthenticated attacker can send requests to /codex/* to bypass the API-key gate and cause the server to make upstream provider calls using operator-stored LLM provider credentials. This issue is fixed in version 0.5.2.
Patch / fix
- npm 9router 0.5.2
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
6.58% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/decolua/9router/security/advisories/GHSA-8gmq-j984-vp4r referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H |
| GitHub | 3.1 | 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | 9router | <0.5.2 |
0.5.2 |
Affected products
- decolua 9router
Classification
References
Sources
- CVE List CVE-2026-55638
- GitHub Advisory GHSA-8gmq-j984-vp4r
- NVD CVE-2026-55638
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