CVE-2025-6515
Reuse of session IDs in oatpp-mcp leads to session hijacking and prompt hijacking by remote attackers
Vexday Risk Score
13Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 6.8EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
20 Oct 2025Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H
Affected products
oatpp · oatpp-mcpWant to know if your infrastructure is exposed to this?
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