CVE-2025-59956
MEDIUMcoder/agentapi < 0.4.0 - Unauthorized Data Exfiltration via DNS Rebinding Attack
Title source: llmDescription
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.
References (7)
Core 7
Core References
Patch, Vendor Advisory x_refsource_confirm
https://github.com/coder/agentapi/security/advisories/GHSA-w64r-2g3w-w8w4
Issue Tracking, Patch x_refsource_misc
https://github.com/coder/agentapi/pull/49
Patch x_refsource_misc
https://github.com/coder/agentapi/commit/5c425c62447b8a9eac19e9fc5a2eae7f0803f149
Technical Description x_refsource_misc
https://github.blog/security/application-security/localhost-dangers-cors-and-dns-rebinding
Release Notes x_refsource_misc
https://github.com/coder/agentapi/releases/tag/v0.4.0
Exploit, Third Party Advisory x_refsource_misc
https://mcpsec.dev/advisories/2025-09-19-coder-chat-exfiltration
Exploit, Third Party Advisory
https://mcpsec.dev/advisories/2025-09-19-coder-chat-exfiltration/
Scores
CVSS v3
6.5
EPSS
0.0040
EPSS Percentile
32.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-290
CWE-350
Status
published
Products (2)
coder/agentapi
< 0.4.0
coder/agentapi
0 - 0.4.0Go
Published
Sep 30, 2025
Tracked Since
Feb 18, 2026