GHSA-h99m-6755-rgwc — rancher
CRITICALGHSA-h99m-6755-rgwc is a critical-severity (CVSS 9.1) Improper Privilege Management vulnerability in github.com/rancher/rancher. A fix is available for github.com/rancher/rancher — see the affected versions and patch details below.
Rancher Remote Code Execution via Cluster/Node Drivers
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-h99m-6755-rgwc.
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-h99m-6755-rgwc 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 377,636 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/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 where a cluster or node driver can be used to escape the chroot jail and gain root access to the Rancher container itself. In production environments, further privilege escalation is possible based on living off the land within the Rancher container itself. For the test and development environments, based on a –privileged Docker container, it is possible to escape the Docker container and gain execution access on the host system.
This happens because:
- During startup, Rancher appends the
/opt/drivers/management-state/bindirectory to thePATHenvironment variable. - In Rancher, the binaries
/usr/bin/rancher-machine,/usr/bin/helm_v3, and/usr/bin/kustomizeare assigned a UID of 1001 and a GID of 127 instead of being owned by the root user. - Rancher employs a jail mechanism to isolate the execution of node drivers from the main process. However, the drivers are executed with excessive permissions.
- During the registration of new node drivers, its binary is executed with the same user as the parent process, which could enable an attacker to gain elevated privileges by registering a malicious driver.
- Lack of validation on the driver file type, which allows symbolic links to be used.
Please consult the associated MITRE ATT&CK - Technique - Privilege Escalation and MITRE ATT&CK - Technique - Execution for further information about this category of attack.
Since they run at a privileged level, it is recommended to use trusted drivers only.
Patches
The fix involves some key areas with the following changes:
Fixing the PATH environment variable:
- Remove the step that appends
/opt/drivers/management-state/binto thePATHenvironment variable.
Binaries permissions:
- Correct the permission of the binaries
/usr/bin/rancher-machine,/usr/bin/helm_v3, and/usr/bin/kustomizeso that they are owned by the root user.
Improving Rancher jail security mechanism:
- A new group
jail-accessorshas been created, and the rancher user has been added to this group. - The
jail-accessorsgroup is granted read and execute permissions for the directories/var/lib/rancher,/var/lib/cattle, and/usr/local/bin. - The jail mechanism has been enhanced to execute commands using the non-root
rancheruser and thejail-accessorsgroup. Additionally, a new setting,UnprivilegedJailUser, has been introduced to manage this behavior, allowing users to opt-out if they need to run drivers in a more privileged context. - Limit the devices copied to the jail directory to a minimal set.
Fixing node driver registration:
- The
NewPlugin(driver)function in therancher/machinemodule has been updated to allow setting the UID and GID for starting the plugin server. If the environment variablesMACHINE_PLUGIN_UIDandMACHINE_PLUGIN_GIDare set, their values will be used to configure the user credentials for launching the plugin server. - Rancher now sets these environment variables with a non-root UID and GID before invoking the
NewPlugin(driver)function and then unsets them after retrieving the creation flags.
Improvements on driver package:
- The
driverpackage has been revised to verify that the downloaded driver binary is a regular file. - The
driverpackage has been revised to verify that the target file in the downloaded tar file is a regular file. - The
driverpackage now executes the downloaded driver binary within a jail, with a default timeout of 5 seconds.
Other improvements:
- The helm package has been updated to ensure appropriate permissions are set on the generated kubeconfig file.
- The
nodeConfigpackage has been updated to ensure proper permissions are applied when extracting the node configuration.
Patched versions include releases 2.7.16, 2.8.9 and 2.9.3.
Workarounds
If you can't upgrade to a fixed version, please make sure that:
- Drivers are only executed from trusted sources.
- The use of Admins/Restricted Admins is limited to trusted users.
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 | ≥ 2.7.0&&< 2.7.16 | 2.7.16go get github.com/rancher/rancher@v2.7.16 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.8.0&&< 2.8.9 | 2.8.9go get github.com/rancher/rancher@v2.8.9 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.9.0&&< 2.9.3 | 2.9.3go get github.com/rancher/rancher@v2.9.3 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/rancher/rancher to 2.7.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h99m-6755-rgwc 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-h99m-6755-rgwc can be triaged on real exposure rather than presence alone.
Tailored to GHSA-h99m-6755-rgwc. 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-h99m-6755-rgwc in your dependencies?
O3 Security finds GHSA-h99m-6755-rgwc across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.