CVE-2025-6515 - CVE House
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Status published Medium CVE-2025-6515

Reuse of session IDs in oatpp-mcp leads to session hijacking and prompt hijacking by remote attackers

Vulnerability Description

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

More from oatpp

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CVE-2025-6566
oatpp Oat++ Deserializer.cpp deserializeArray stack-based overflow
Medium 6.9

Affected Vendor

Affected Software

oatpp-mcp
Vulnerable Versions:
0

Timeline

Official Publish: October 20th, 2025
Last Modified: October 20th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H

Weaknesses (CWE)

CWE-330

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.