Medium severity · published Sep 4, 2026
CVE-2026-85700
Onyx 4.6.6 Custom Tool Secret Header Disclosure via Tool Endpoints
6.5
CVSS
0.5%
EPSS
No
On KEV
Description
Onyx 4.6.6 fails to properly restrict access to custom tool credentials stored in custom_headers, allowing any authenticated user to read admin-defined API keys. Attackers with basic authentication can call GET /tool/{tool_id} or GET /tool endpoints to retrieve plaintext authorization headers and third-party API credentials, then use them to directly access upstream APIs.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ON
onyx · onyx-dot-app
through 4.6.6 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-85700
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-85700
github.com
https://github.com/onyx-dot-app/onyx
github.com
https://github.com/onyx-dot-app/onyx/blob/v4.6.6/backend/onyx/server/features/tool/api.py
github.com
https://github.com/onyx-dot-app/onyx/blob/v4.6.6/backend/onyx/server/features/tool/models.py
github.com
https://github.com/onyx-dot-app/onyx/issues/13165
www.vulncheck.com
https://www.vulncheck.com/advisories/onyx-4.6.6-custom-tool-secret-header-disclosure-via-tool-endpoints
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