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Medium severity · published Sep 3, 2026
CVE-2026-71403
Rancher: Identity-field mutation in /v3/users allows account hijack via principal rebind
6.1
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RA
Rancher · SUSE
before 2.15.1 · source: vendor, NVD
Affected product
RA
Rancher
SUSE
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-71403
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-71403
Issue Tracking
https://github.com/rancher/rancher/pull/56616
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