CVE-2024-43798: Chisel is a fast TCP/UDP tunnel, transported over HTTP, secured via SSH. The Chisel server doesn't ever read the documented `AUTH` environment variabl...

Description

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.

Metrics

CVSS 3.1

8.6/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS Probability

0.45%

35.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

https://github.com/jpillora/chisel/security/advisories/GHSA-38jh-8h67-m7mj

Timeline

Published: Aug 26, 2024
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2024-43798?

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.

How severe is CVE-2024-43798?

CVE-2024-43798 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 0.45% probability of exploitation in the next 30 days.

How do I fix CVE-2024-43798?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.