MCP DNS-rebinding origin check in AshAi is bypassed by a spoofed X-Forwarded-Proto header
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| ash-project | ash_ai | unaffected |
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| ash-project | ash_ai | unaffected |
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No data.
No data.
| Vendor | Product | Versions | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Ash-project | Ash Ai |
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| Ash-project | Ash Ai |
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No CVSS v3.1
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.278% probability within 30 days)
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| Metrics |
ssvc
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| Description | Origin Validation Error vulnerability in ash-project ash_ai allows a malicious web page to bypass the MCP server's DNS-rebinding protection and issue cross-site requests to a user's local MCP server with that user's actor. In AshAi.Mcp.Server, with the default allowed_origins: nil, origin_allowed?/3 accepts an origin when uri.host == conn.host and the forwarded scheme is https. Both values are attacker-controlled: conn.host comes from the Host header and the scheme is read from the raw x-forwarded-proto header with no trusted-proxy check. Under DNS rebinding the browser sends the attacker's origin and a matching host, and page JavaScript may set X-Forwarded-Proto: https, so the check passes with no TLS or proxy involved. The fix trusts only localhost origins by default; other origins require an explicit allowed_origins allowlist. This issue affects ash_ai: from 0.8.0 before 1.0.0. | |
| Title | MCP DNS-rebinding origin check in AshAi is bypassed by a spoofed X-Forwarded-Proto header | |
| First Time appeared |
Ash-project
Ash-project ash Ai |
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| Weaknesses | CWE-346 | |
| CPEs | cpe:2.3:a:ash-project:ash_ai:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Ash-project
Ash-project ash Ai |
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| References |
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| Metrics |
cvssV4_0
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