CVE-2026-16141

OpenBMC IPMI Authentication Bypass via Default userKey and Stale Challenge Value

Published Sep 15, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Openbmc
Openbmc phosphor-net-ipmid
Vendors & Products Openbmc
Openbmc phosphor-net-ipmid
Type Values Removed Values Added
Metrics ssvc

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
runZero
Published
Updated
Sep 15, 2026, 2:59 PM
Reserved
Jul 17, 2026, 5:17 PM
Status
Awaiting Analysis
Published
Sep 15, 2026, 2:16 PM
Modified
Sep 18, 2026, 7:30 PM