Session hijacking via reused pointer-derived identifiers
Published Oct 20, 2025 · Updated Oct 20, 2025
Session hijacking in Oat++ oatpp-mcp version 0 allows remote attackers to inject malicious MCP responses through reused SSE session IDs. Session::getId() converts the Session object's address to a decimal identifier, and allocator reuse can assign a previously disclosed value to a new client. Exploitation requires network access, HTTP SSE transport, identifier reuse, and a client that accepts the attacker's injected event.
Summary
What happened
Session hijacking in Oat++ oatpp-mcp version 0 allows remote attackers to inject malicious MCP responses through reused SSE session IDs. Session::getId() converts the Session object's address to a decimal identifier, and allocator reuse can assign a previously disclosed value to a new client. Exploitation requires network access, HTTP SSE transport, identifier reuse, and a client that accepts the attacker's injected event.
The record
- CVE
- CVE-2025-6515
- Published
- Oct 20, 2025
- Updated
- Oct 20, 2025
- Vendor
- Oat++
- Product
- oatpp-mcp
- Classifications
- CWE-330, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 20, 2025CVE publishedPublication date reported by the CVE source.
- Oct 20, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- JFrog oatpp-mcp prompt-hijacking demonstrationfunctional · demonstrated
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Technologies
Your stack
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Your stack
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