CVE-2026-71403 — Rancher: Identity-field mutation in /v3/users allows account hijack via principal rebind
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…
Published: 2026-09-03 · CVSS: 6.1 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7