CVE-2026-59973 FrontMCP - Server Side Request Forgery

FrontMCP mcp-from-openapi 2.3.0 to 2.5.0 and frontmcp & @frontmcp/adapters 1.2.1 to 1.5.0 contain a server-side request forgery caused by improper validation of external $ref URLs in OpenAPI specs, letting authenticated users access internal network services, exploit requires authenticated user able to import or configure OpenAPI specs.

CVSS base score 8.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.39% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Server Side Request Forgery
Impact
Server Side Request Forgery, Information Disclosure
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Published
15 September 2026
Updated
15 October 2026
Weakness
CWE-918

Vendor fix

Update to mcp-from-openapi 2.5.0 and frontmcp & @frontmcp/adapters 1.5.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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