6.9 MEDIUM
- CVSS version (CVSS): 4.0
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Attack Requirement (AT): Present (P)
- Privileges Required (PR): None (N)
- User Interaction (UI): Active (A)
- Vulnerable System Impact Confidentiality (VC): High (H)
- Vulnerable System Impact Integrity (VI): None (N)
- Vulnerable System Impact Availability (VA): None (N)
- Subsequent System Impact Confidentiality (SC): High (H)
- Subsequent System Impact Integrity (SI): None (N)
- Subsequent System Impact Availability (SA): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): Low (L)
- Modified Attack Requirement (MAT): Present (P)
- Modified Privileges Required (MPR): None (N)
- Modified User Interaction (MUI): Active (A)
- Modified Vulnerable System Impact Confidentiality (MVC): High (H)
- Modified Vulnerable System Impact Integrity (MVI): None (N)
- Modified Vulnerable System Impact Availability (MVA): None (N)
- Modified Subsequent System Impact Confidentiality (MSC): High (H)
- Modified Subsequent System Impact Integrity (MSI): Negligible (N)
- Modified Subsequent System Impact Availability (MSA): Negligible (N)
- Safety (S): Not Defined (X)
- Automatable (AU): Not Defined (X)
- Recovery (R): Not Defined (X)
- Value Density (V): Not Defined (X)
- Vulnerability Response Effort (RE): Not Defined (X)
- Provider Urgency (U): Not Defined (X)
- Confidentiality Req. (CR): Not Defined (X)
- Integrity Req. (IR): Not Defined (X)
- Availability Req. (AR): Not Defined (X)
- Exploit Maturity (E): Not Defined (X)
Activity log
- Created & dismissed (no matching packages found) suggestion
MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection
MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a locally running MCP server and invoke exposed tools. This issue is fixed in version 0.23.0.
References
-
https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-rjr6-rcgv-9m7m x_refsource_CONFIRMexploit
Affected products
- ==< 0.23.0