CVE-2026-71403 Rancher: Identity-field mutation in /v3/users allows account hijack via principal rebind
Attackers with update permissions can hijack accounts by rebinding identity principals, leading to unauthorized access and privilege escalation in Rancher.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-71403?
CVE-2026-71403 is a medium-severity authentication bypass vulnerability in SUSE Rancher, published on 3 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
A flaw was found in Rancher Manager. The /v3/users update path did not enforce immutability of a User resource's `username` and `principalIds` fields. A user holding the `update` verb on `users.management.cattle.io` could inject a foreign identity provider principal into any account, so that the next login by the owner of that principal was bound to the victim's account and inherited its role bindings.
This issue affects Rancher: before 2.15.1.
Weakness: CWE-639
Which versions are affected by CVE-2026-71403?
It affects 1 product.
Products include Suse Rancher.
How do I fix CVE-2026-71403?
No fix has been published for CVE-2026-71403 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-71403 being exploited?
There is no known exploitation of CVE-2026-71403 in the wild and no public exploit code.
Other vulnerabilities in SUSE Rancher
- CVE-2023-22647 Rancher vulnerable to Privilege Escalation via manipulation of Secrets
- CVE-2023-22651 Rancher Webhook is misconfigured during upgrade process
- CVE-2022-43757 Rancher: Exposure of sensitive fields
- CVE-2021-36782 Rancher: Plaintext storage and exposure of credentials in Rancher API and cluster.management.cattle.io object
- CVE-2021-36783 Rancher: Failure to properly sanitize credentials in cluster template answers