CVE-2024-43798 — chisel
HIGHCVE-2024-43798 is a high-severity (CVSS 8.6) Missing Authentication vulnerability in github.com/jpillora/chisel. A fix is available for github.com/jpillora/chisel — see the affected versions and patch details below.
Chisel AUTH environment variable not respected in server entrypoint
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-43798.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2024-43798 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 388,997 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/jpillora/chiselReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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. This advisory is a formalization of a report sent to the maintainer via email.
Details
In the help page for the chisel server subcommand, it mentions an AUTH environment variable that can be set in order to provide credentials that the server should authenticate connections against: https://github.com/jpillora/chisel/blob/3de177432cd23db58e57f376b62ad497cc10840f/main.go#L138.
The issue is that the server entrypoint doesn't ever read the AUTH environment variable. The only place that this happens is in the client entrypoint: https://github.com/jpillora/chisel/blob/3de177432cd23db58e57f376b62ad497cc10840f/main.go#L452
This subverts the expectations set by the documentation, allowing unauthenticated users to connect to a Chisel server, even if auth is attempted to be set up in this manner.
PoC
Run chisel server, first specifying credentials with the AUTH environment variable, then with the --auth argument. In the first case, the server allows connections without authentication, while in the second, the correct behavior is exhibited.
Impact
Anyone who is running the Chisel server, and that is using the AUTH environment variable to specify credentials to authenticate against. 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/jpillora/chisel | all versions | 1.10.0go get github.com/jpillora/chisel@v1.10.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/jpillora/chisel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/jpillora/chisel to 1.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-43798 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2024-43798 in your dependencies?
Find it across Go, including transitive dependencies.