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.
Blast Radius
cargoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
The Rust Security Response WG was notified that Cargo did not perform SSH host key verification when cloning indexes and dependencies via SSH. An attacker could exploit this to perform man-in-the-middle (MITM) attacks.
This vulnerability has been assigned CVE-2022-46176.
Overview
When an SSH client establishes communication with a server, to prevent MITM attacks the client should check whether it already communicated with that server in the past and what the server's public key was back then. If the key changed since the last connection, the connection must be aborted as a MITM attack is likely taking place.
It was discovered that Cargo never implemented such checks, and performed no validation on the server's public key, leaving Cargo users vulnerable to MITM attacks.
Affected Versions
All Rust versions containing Cargo before 1.66.1 are vulnerable (prior to 0.67.1 for the crates.io package).
Note that even if you don't explicitly use SSH for alternate registry indexes or crate dependencies, you might be affected by this vulnerability if you have configured git to replace HTTPS connections to GitHub with SSH (through git's url.<base>.insteadOf setting), as that'd cause you to clone the crates.io index through SSH.
Mitigations
We will be releasing Rust 1.66.1 today, 2023-01-10, changing Cargo to check the SSH host key and abort the connection if the server's public key is not already trusted. We recommend everyone to upgrade as soon as possible.
Patch files for Rust 1.66.0 are also available here for custom-built toolchains.
For the time being Cargo will not ask the user whether to trust a server's public key during the first connection. Instead, Cargo will show an error message detailing how to add that public key to the list of trusted keys. Note that this might break your automated builds if the hosts you clone dependencies or indexes from are not already trusted.
If you can't upgrade to Rust 1.66.1 yet, we recommend configuring Cargo to use the git CLI instead of its built-in git support. That way, all git network operations will be performed by the git CLI, which is not affected by this vulnerability. You can do so by adding this snippet to your Cargo configuration file:
[net]
git-fetch-with-cli = true
Acknowledgments
Thanks to the Julia Security Team for disclosing this to us according to our security policy!
We also want to thank the members of the Rust project who contributed to fixing this issue. Thanks to Eric Huss and Weihang Lo for writing and reviewing the patch, Pietro Albini for coordinating the disclosure and writing this advisory, and Josh Stone, Josh Triplett and Jacob Finkelman for advising during the disclosure.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | cargo | all versions | 0.67.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cargo. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update cargo to 0.67.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r5w3-xm58-jv6j 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 pinpoints whether GHSA-r5w3-xm58-jv6j is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-r5w3-xm58-jv6j. 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-r5w3-xm58-jv6j in your dependencies?
O3 detects GHSA-r5w3-xm58-jv6j across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.