CVE Catalog

CVE-2025-6515

MediumCVSS 6.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.40%

32th percentile - higher than 32% of all known CVEs

Summary

The MCP SSE endpoint in oatpp-mcp returns an instance pointer as the session ID, which is not unique nor cryptographically secure. This allows network attackers with access to the oatpp-mcp server to guess future session IDs and hijack legitimate client MCP sessions, returning malicious responses from the oatpp-mcp server.

Risk Assessment

Attackers may hijack MCP client sessions, potentially leading to response manipulation and integrity compromise.

Recommendation

Update oatpp-mcp to a version with proper session ID generation and implement additional session authentication mechanisms.

Related vulnerabilities

Original NVD description (English source)

The MCP SSE endpoint in oatpp-mcp returns an instance pointer as the session ID, which is not unique nor cryptographically secure. This allows network attackers with access to the oatpp-mcp server to guess future session IDs and hijack legitimate client MCP sessions, returning malicious responses from the oatpp-mcp server.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS