CVE-2025-6515CWE-330

CVE-2025-6515

Medium · published October 20, 2025

CVSS v3.1
6.8
EPSS
0%
Percentile
33.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.8 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00401 · 33.2th percentile
Weakness
CWE-330 · Use of Insufficiently Random Values
Published
2025-10-20T21:15Z
References (1)
https://research.jfrog.com/vulnerabilities/oatpp-mcp-prompt-hijacking-jfsa-2025-001494691/ · [email protected]
EPSS history
Timeline
  • 20 OCT 16:13Z
    Reuse of session IDs in oatpp-mcp leads to session hijacking and prompt hijacking by remote attackers
    cvelistv5