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2 vulnerabilities by mcp-use
CVE-2026-81091 (GCVE-0-2026-81091)
Vulnerability from nvd – Published: 2026-08-27 14:50 – Updated: 2026-08-29 11:48
VLAI
EPSS
VEX
Title
mcp-use Inspector Proxy Server-Side Request Forgery via Caller-Supplied Target URL
Summary
The proxy middleware in mcp-use's inspector forwards requests to a destination the caller names. mountMcpProxy in libraries/typescript/packages/inspector/src/server/proxy/mcp-proxy.ts read the target from the X-Target-URL header or the __mcp_target parameter and proxied to it without inspecting the host, so loopback, link-local and private addresses were all accepted, as were names that resolve to them, and the validation was not reapplied to a redirect the destination returned. A caller could therefore make the server issue requests to addresses reachable only from the host it runs on and read the responses. The current code calls isSafeProxyTarget, which checks the resolved address against private, loopback and link-local ranges before proxying and bounds the number of redirects followed.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-27 18:12 UTC
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/mcp-use/mcp-use | product |
| https://github.com/mcp-use/mcp-use/security/advis… | vendor-advisory |
| https://www.vulncheck.com/advisories/mcp-use-insp… | third-party-advisory |
Date Public
2026-08-26 00:00
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CVE-2026-81091 (GCVE-0-2026-81091)
Vulnerability from cvelistv5 – Published: 2026-08-27 14:50 – Updated: 2026-08-29 11:48
VLAI
EPSS
VEX
Title
mcp-use Inspector Proxy Server-Side Request Forgery via Caller-Supplied Target URL
Summary
The proxy middleware in mcp-use's inspector forwards requests to a destination the caller names. mountMcpProxy in libraries/typescript/packages/inspector/src/server/proxy/mcp-proxy.ts read the target from the X-Target-URL header or the __mcp_target parameter and proxied to it without inspecting the host, so loopback, link-local and private addresses were all accepted, as were names that resolve to them, and the validation was not reapplied to a redirect the destination returned. A caller could therefore make the server issue requests to addresses reachable only from the host it runs on and read the responses. The current code calls isSafeProxyTarget, which checks the resolved address against private, loopback and link-local ranges before proxying and bounds the number of redirects followed.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-27 18:12 UTC
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/mcp-use/mcp-use | product |
| https://github.com/mcp-use/mcp-use/security/advis… | vendor-advisory |
| https://www.vulncheck.com/advisories/mcp-use-insp… | third-party-advisory |
Date Public
2026-08-26 00:00
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