CVE-2025-6515

Severity CVSS v4.0:

Pending analysis

Type:

CWE-330 Use of Insufficiently Random Value

Publication date:

20/10/2025

Last modified:

21/10/2025

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

Vector 3.x

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 6.80 MEDIUM
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): High
Availability (A): High

Base Score 3.x

6.80

Severity 3.x

MEDIUM

References to Advisories, Solutions, and Tools

https://research.jfrog.com/vulnerabilities/oatpp-mcp-prompt-hijacking-jfsa-2025-001494691/