Mathew Gale@Mattjgale87
Disclosure
• Jul 2026 — CVE-2025-6515: MCP session hijacking goes public
Post summary
CVEs‑2025‑6515, an MCP session hijacking vulnerability, has just been publicly disclosed.
0000047
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CVE-2025-6515Disclosure
LOWCVSS 6.8 · MEDIUMSignal is active with 1 mentions in latest observed window
Immediate actions
- Track advisory updates for patch or workaround availability
Recommended action window: Monitor and triage in normal cycle
NVD 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.
0.0/ 10 priority
Sources & remediation
Other references
Weakness type (CWE)
CWE-330
Priority
LOW
Exploitation
NONE
PoC
NONE
Patch
NONE
Momentum
STABLE
Threat summary
- 2 mentions across 2 observed days
- Momentum state: stable
What's happening
- Disclosure: 2 classified signals
- Peaked 1d ago at 1 mentions (2026-08-01); latest day: 1
- 2 total mentions across 2 days
Deep dive
Activity timeline2 mentions / 2d
Signal classification1 categories
Disclosure2100.0%
Full discourse2 posts
- Mathew Gale@Mattjgale87Disclosure
• Jul 2026 — CVE-2025-6515: MCP session hijacking goes public
Post summary
The text announces that CVE‑2025‑6515, a session hijacking flaw in MCP, has been made public, indicating an initial disclosure of the vulnerability without further details.
000004057 followersView on X