CVE-2021-36784 — rancher
HIGHCVE-2021-36784 is a high-severity (CVSS 7.2) 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.
Privilege escalation for users with create/update permissions in Global Roles in Rancher
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
CVE-2021-36784 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 378,156 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/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
This vulnerability affects customers who utilize non-admin users that are able to create or edit Global Roles. The most common use case for this scenario is the restricted-admin role.
A flaw was discovered in Rancher versions from 2.5.0 up to and including 2.5.12 and from 2.6.0 up to and including 2.6.3 which allows users who have create or update permissions on Global Roles to escalate their permissions, or those of another user, to admin-level permissions. Global Roles grant users Rancher-wide permissions, such as the ability to create clusters. In the identified versions of Rancher, when users are given permission to edit or create Global Roles, they are not restricted to only granting permissions which they already posses.
The privilege escalation can be taken advantage of in two ways by users with create or update permissions on Global Roles (including the restricted-admin):
- Editing the global
adminrole to make it the default for new users, then creating a new user that will be elevated to the globaladminrole. - Creating a new global role with permissions already possessed by the
restricted-admin, assigning this new role to a user, then modifying the global role to grant additional administrive like permissions ('*') to the elevated user.
Patches
Patched versions include releases 2.5.13, 2.6.4 and later versions.
Workarounds
Limit access in Rancher to trusted users. There is not a direct mitigation besides upgrading to the patched Rancher versions.
Note: If you have users who have create or edit permissions on Global Roles but are not admin users (for example, the restricted-admin), it is highly advised to review the roles and users created by those users for possible privilege escalations.
For more information
If you have any questions or comments about this advisory:
- Reach out to SUSE Rancher Security team for security related inquiries.
- Open an issue in Rancher repository.
- Verify our support matrix and product support lifecycle.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/rancher/rancher | ≥ 2.6.0&&< 2.6.4 | 2.6.4go get github.com/rancher/rancher@v2.6.4 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.5.0&&< 2.5.13 | 2.5.13go get github.com/rancher/rancher@v2.5.13 |
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 2.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-36784 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 CVE-2021-36784 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-36784. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-36784 in your dependencies?
O3 Security finds CVE-2021-36784 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.