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Fencer Intel
medium 6.1

CVE-2026-71403 json

Rancher: Identity-field mutation in /v3/users allows account hijack via principal rebind

published 2mo ago modified last mo. also EUVD-2026-70501

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • SUSE Rancher 2.15.1

Is CVE-2026-71403 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N

Affected products

  • SUSE Rancher

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.