CVE-2025-59956
AgentAPI exposed user chat history via a DNS rebinding attack
- State
- Published
- Severity
- 6.5 Medium
- Published
- Sep 29, 2025
- Updated
- Sep 30, 2025
- Reserved
- Sep 23, 2025
Description
AgentAPI is an HTTP API for Claude Code, Goose, Aider, Gemini, Amp, and Codex. Versions 0.3.3 and below are susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost. An attacker can gain access to the /messages endpoint served by the Agent API. This allows for the unauthorized exfiltration of sensitive user data, specifically local message history, which can include secret keys, file system contents, and intellectual property the user was working on locally. This issue is fixed in version 0.4.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N | GitHub_M |
Weaknesses
- CWE-350 Reliance on Reverse DNS Resolution for a Security-Critical Action
Affected Products
| Product | Versions |
|---|---|
agentapicoder |
|
References
- https://github.com/coder/agentapi/security/advisories/GHSA-w64r-2g3w-w8w4
- https://github.com/coder/agentapi/pull/49
- https://github.com/coder/agentapi/commit/5c425c62447b8a9eac19e9fc5a2eae7f0803f149
- https://github.blog/security/application-security/localhost-dangers-cors-and-dns-rebinding
- https://github.com/coder/agentapi/releases/tag/v0.4.0
- https://mcpsec.dev/advisories/2025-09-19-coder-chat-exfiltration
- https://mcpsec.dev/advisories/2025-09-19-coder-chat-exfiltration/exploit
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