What’s Vulnerable › Vulnerabilities

CVE-2026-16141: OpenBMC IPMI Authentication Bypass via Default userKey and Stale Challenge Value

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-09-18
• Weakness: CWE-457

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.

References

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

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