Headline
GHSA-w64r-2g3w-w8w4: Coder AgentAPI exposed user chat history via a DNS rebinding attack
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.
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.