OpenBMC's IPMI implementation, phosphor-net-ipmid, contains a logic flaw in which an unauthenticated client can force the RAKP Message 1 handler to return before it overwrites the authentication object's constructor defaults. The IPMI service then accepts a RAKP Message 3 whose HMAC is computed with the constant 20-byte 'userKey' initialized from the string '0penBmc' and an often-predictable 'bmcRandomNum'. Several downstream vendors implement phosphor-net-ipmid as their IPMI stack, such as NVIDIA and H3C.

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Fixes

Solution

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Workaround

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History

Thu, 17 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Openbmc
Openbmc phosphor-net-ipmid
Vendors & Products Openbmc
Openbmc phosphor-net-ipmid

Tue, 15 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 15 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
References

Tue, 15 Sep 2026 14:00:00 +0000

Type Values Removed Values Added
Description OpenBMC's IPMI implementation, phosphor-net-ipmid, contains a logic flaw in which an unauthenticated client can force the RAKP Message 1 handler to return before it overwrites the authentication object's constructor defaults. The IPMI service then accepts a RAKP Message 3 whose HMAC is computed with the constant 20-byte 'userKey' initialized from the string '0penBmc' and an often-predictable 'bmcRandomNum'. Several downstream vendors implement phosphor-net-ipmid as their IPMI stack, such as NVIDIA and H3C.
Title OpenBMC IPMI Authentication Bypass via Default userKey and Stale Challenge Value
Weaknesses CWE-457
CWE-798
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: runZero

Published:

Updated: 2026-09-15T14:59:11.232Z

Reserved: 2026-07-17T17:17:25.183Z

Link: CVE-2026-16141

cve-icon Vulnrichment

Updated: 2026-09-15T14:59:06.110Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-15T14:16:50.430

Modified: 2026-09-18T19:30:42.730

Link: CVE-2026-16141

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-17T19:59:07Z

Weaknesses