CVE-2026-71403

medium

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.

References

https://github.com/rancher/rancher/pull/56616

Details

Source: Mitre, NVD

Published: 2026-09-03

Updated: 2026-09-08

Risk Information

CVSS v2

Base Score: 7.7

Vector: CVSS2#AV:N/AC:L/Au:M/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 6.1

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N

Severity: Medium

EPSS

EPSS: 0.00197