GHSA-38jh-8h67-m7mj — chisel
HIGHGHSA-38jh-8h67-m7mj 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's 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 GHSA-38jh-8h67-m7mj.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-38jh-8h67-m7mj plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 GHSA-38jh-8h67-m7mj is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-38jh-8h67-m7mj can be triaged on real exposure rather than presence alone.
Tailored to GHSA-38jh-8h67-m7mj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-38jh-8h67-m7mj in your dependencies?
O3 Security finds GHSA-38jh-8h67-m7mj across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.