Coder AgentAPI exposed user chat history via a DNS rebinding attack

中 6.5CVE-2025-59956 · GHSA-w64r-2g3w-w8w4 · GO-2025-3991 · 30/09/2025 公開 · 17/06/2026 更新

要点

CVE-2025-59956 は github.com/coder/agentapi, agentapi (coder) に影響する深刻度「中」 (CVSS 6.5) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.43%（全脆弱性の 36.9% より高い）。
対処：0.4.0 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
github.com/coder/agentapi Go	`< 0.4.0`	`0.4.0`
agentapi coder	`< 0.4.0`	`0.4.0`

概要

Summary

AgentAPI prior to version 0.4.0 was susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost.

Impact

An attacker could have gained access to the /messages endpoint served by the Agent API. This allowed for the unauthorized exfiltration of sensitive user data, specifically local message history, which could've included secret keys, file system contents, and intellectual property the user was working on locally.

Remediation

We've implemented an Origin and Host header validating middleware and set a secure by default configuration.

Please upgrade to version 0.4.0 or later.

Credits

We'd like to thank Evan Harris from mcpsec.dev for reporting this issue and following the coordinated disclosure policy.

NVD の説明

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.