CVE-2026-71424 json
Onyx: Cross-user OAuth-token leak via /api/mcp/servers* for per-user MCP servers
published 2026-08-17 2 mo ago modified 2026-10-22 17 d ago also EUVD-2026-60479
- cvss
- 9.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
Onyx is an open-source AI platform. Prior to 3.1.10, 3.2.14, and 4.0.0, Onyx's GET /api/mcp/servers and GET /api/mcp/servers/persona/{persona_id} endpoints expose another user's OAuth Authorization header because OnyxTokenStorage.set_tokens and OnyxTokenStorage.set_client_info in backend/onyx/server/features/mcp/api.py copy per-user tokens into a shared admin MCPConnectionConfig row and _db_mcp_server_to_api_mcp_server returns that row through auth_template.headers to any BASIC_ACCESS user. This issue is fixed in versions 3.1.10, 3.2.14, and 4.0.0.
Patch / fix
- onyx onyx 3.1.10, 3.2.14, 4.0.0
- github.com/onyx-dot-app/onyx@3f3d79d commit
- github.com/onyx-dot-app/onyx@4001ced commit
- github.com/onyx-dot-app/onyx@b103937 commit
- github.com/onyx-dot-app/onyx#11238 pull request
- github.com/onyx-dot-app/onyx#11242 pull request
- github.com/onyx-dot-app/onyx#11243 pull request
- github.com/onyx-dot-app/onyx/releases/tag/v4.0.0 release
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 mo ago
Exploit prediction
0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
Affected products
- onyx-dot-app onyx
Classification
References
- github.com /onyx-dot-app/onyx/pull/11238
- github.com /onyx-dot-app/onyx/pull/11242
- github.com /onyx-dot-app/onyx/pull/11243
- github.com /onyx-dot-app/onyx/commit/3f3d79d1a7722fdc84a1c61c8aa830d890017e9e
- github.com /onyx-dot-app/onyx/commit/4001cedd0a8968723bfe95dd188914ed56777910
- github.com /onyx-dot-app/onyx/commit/b103937888fd5008067c2bb6eb6e5424576394f2
- github.com /onyx-dot-app/onyx/security/advisories/GHSA-q62f-rv3h-f822
- github.com /onyx-dot-app/onyx/releases/tag/v4.0.0
Sources
- CVE List CVE-2026-71424
- NVD CVE-2026-71424
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.