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CVE-2026-71403

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

Published: Sep 3, 2026Updated: Sep 4, 2026 Sources: CVE List NVDCWE-639
6.1MEDIUM
NVD MITRE
EPSS Score
0.2%
Top 90.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:HUI:RS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:HPrivileges Required
High
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-639

Affected Products

SUSE
commercial·DE
RancherOn-prem
DevTools & CI / ci-cd

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

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

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