GHSA-mjcp-rj3c-36fr
MEDIUMGHSA-mjcp-rj3c-36fr is a medium-severity (CVSS 4.7) Information Exposure vulnerability in github.com/rancher/rancher. O3 Security confirms whether GHSA-mjcp-rj3c-36fr is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Rancher sends sensitive information to external services through the `/meta/proxy` endpoint
Blast Radius
github.com/rancher/rancher🐹github.com/rancher/rancher🐹github.com/rancher/rancher🐹github.com/rancher/rancherReal-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
Impact
A vulnerability has been identified within Rancher Manager whereby Impersonate-Extra-* headers are being sent to an external entity, for example amazonaws.com, via the /meta/proxy Rancher endpoint. These headers may contain identifiable and/or sensitive information e.g. email addresses.
If the authentication provider is configured to have email or other sensitive and/or identifiable information as part of the username and principal ID then when a new cloud credential is being created in Rancher Manager this information is sent to an external entity such as amazonaws.com, in case of an AWS cloud credentials, in Impersonate-Extra-Username and/or Impersonate-Extra-Principalid headers. Please note that neither password, password hashes or Rancher’s related authentication tokens are leaked in those requests.
The entities to which such information is sent to are limited by the whitelisted domains specified in nodedrivers.management.cattle.io objects.
For example, the Amazon EC2 node driver contains the following whitelisted domains:
iam.amazonaws.comiam.us-gov.amazonaws.comiam.%.amazonaws.com.cniam.global.api.awsec2.%.amazonaws.comec2.%.amazonaws.com.cnec2.%.api.awseks.%.amazonaws.comeks.%.amazonaws.com.cneks.%.api.awskms.%.amazonaws.comkms.%.amazonaws.com.cnkms.%.api.aws
While the DigitalOcean driver contains the following whitelisted domain:
api.digitalocean.com
Patches
This vulnerability is addressed by filtering all Impersonate-* headers from the original request by the /meta/proxy endpoint.
Patched versions of Rancher include releases v2.12.2, v2.11.6, v2.10.10, and v2.9.12.
Workarounds
There are no known workarounds for this issue.
References
If you have any questions or comments about this advisory:
- Reach out to the SUSE Rancher Security team for security related inquiries.
- Open an issue in the Rancher repository.
- Verify with our support matrix and product support lifecycle.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/rancher/rancher | ≥ 2.12.0&&< 2.12.2 | 2.12.2 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.11.0&&< 2.11.6 | 2.11.6 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.10.0&&< 2.10.10 | 2.10.10 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.9.0&&< 2.9.12 | 2.9.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/rancher/rancher. 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 github.com/rancher/rancher to 2.12.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mjcp-rj3c-36fr 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-mjcp-rj3c-36fr 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-mjcp-rj3c-36fr. 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-mjcp-rj3c-36fr in your dependencies?
O3 detects GHSA-mjcp-rj3c-36fr across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.