CVE-2026-16141

OpenBMC IPMI Authentication Bypass via Default userKey and Stale Challenge Value

State: Published
Severity: 8.1 High
Published: Sep 15, 2026
Updated: Sep 15, 2026
Reserved: Jul 17, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	runZero

Weaknesses

CWE-798 Use of Hard-coded Credentials
CWE-457 Use of Uninitialized Variable

Affected Products

Product	Versions
phosphor-net-ipmidOpenBMC	ba6efc502e6b1fabb8ed1ca677ae5eedd64b6361 and earlierAffected

References

https://www.runzero.com/advisories/openbmc-ipmi-auth-bypass-rakp-cve-2026-16141/third-party-advisory
https://www.runzero.com/blog/lights-out-exposed/related

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