Summary
Privilege escalation for users with create/update permissions in Global Roles in Rancher
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.
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.
The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access. Typical impact: privilege escalation beyond the intended level.
CVE-2021-36784 has a CVSS score of 6.5 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.6.4, 2.5.13); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Patched versions include releases 2.5.13, 2.6.4 and later versions.
Frequently Asked Questions
- What is CVE-2021-36784? CVE-2021-36784 is a medium-severity improper privilege management vulnerability in github.com/rancher/rancher (go), affecting versions >= 2.6.0, < 2.6.4. It is fixed in 2.6.4, 2.5.13. The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access.
- How severe is CVE-2021-36784? CVE-2021-36784 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/rancher/rancher are affected by CVE-2021-36784? github.com/rancher/rancher (go) versions >= 2.6.0, < 2.6.4 is affected.
- Is there a fix for CVE-2021-36784? Yes. CVE-2021-36784 is fixed in 2.6.4, 2.5.13. Upgrade to this version or later.
- Is CVE-2021-36784 exploitable, and should I be worried? Whether CVE-2021-36784 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-36784 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-36784?
- Upgrade
github.com/rancher/rancherto 2.6.4 or later - Upgrade
github.com/rancher/rancherto 2.5.13 or later
- Upgrade