Chisel

Chisel is a TCP/UDP tunnel, transported over HTTP and secured via SSH. In versions prior to 1.11.5, authenticated clients can bypass --authfile ACL restrictions and tunnel traffic to arbitrary destinations reachable from the server. The ACL is enforced only during the initial handshake against declared remotes, but never on subsequent SSH channels that carry actual traffic. A malicious client can authenticate with a permitted remote, then open channels to any host:port it wants. This issue has been fixed in version 1.11.5.

Published: 2026-08-03T21:05:14.179Z
Updated: 2026-08-04T17:04:25.711Z

Chisel is a fast TCP/UDP tunnel, transported over HTTP, secured via SSH. The Chisel server doesn't ever read the documented `AUTH` environment variable used to set credentials, which allows any unauthenticated user to connect, even if credentials were set. Anyone running the Chisel server that is using the `AUTH` environment variable to specify credentials to authenticate against is affected by this vulnerability. Chisel is often used to provide an entrypoint to a private network, which means services that are gated by Chisel may be affected. Additionally, Chisel is often used for exposing services to the internet. An attacker could MITM requests by connecting to a Chisel server and requesting to forward traffic from a remote port. This issue has been addressed in release version 1.10.0. All users are advised to upgrade. There are no known workarounds for this vulnerability.

Published: 2024-08-26T22:32:43.575Z
Updated: 2024-08-27T13:06:11.097Z