CVE-2021-39296
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn OpenBMC 2.9, crafted IPMI messages allow an attacker to bypass authentication and gain full control of the system.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceIn OpenBMC 2.9, the IPMI handler fails to properly validate authentication credentials when processing certain crafted IPMI messages, allowing an unauthenticated attacker to bypass authentication entirely and execute administrative commands on the BMC.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 2.9.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify OpenBMC versionRun `cat /etc/os-release` or use `obmcutil --version` to display the installed OpenBMC versionAffected if Version shows exactly 2.9.0
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Verify IPMI service is activeCheck if the IPMI handler service is running by inspecting `systemctl status phosphor-ipmi-host` or checking for IPMI-related processesAffected if IPMI service is running and exposed on the network
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Confirm IPMI over LAN is enabledInspect IPMI configuration at `/etc/phosphor-ipmi-host.cfg` or run `ipmitool lan print 1` to check if IPMI network interface is configured and enabledAffected if IPMI over LAN is enabled and bound to an accessible network interface
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Check IPMI authentication configurationReview `/etc/phosphor-ipmi-host/` directory contents or use `ipmitool user list 1` to enumerate IPMI users and confirm authentication is nominally required but may be bypassedAffected if IPMI authentication appears configured but the service is reachable from untrusted network
Environment is affected if running OpenBMC 2.9.0 and the IPMI service is active and accessible on the network.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpdate OpenBMC to a patched version beyond 2.9. If immediate patching is not possible, restrict network access to the BMC/IPMI interface to trusted networks only.
OpenBMC 2.10.0 or later
- 1. Identify the OpenBMC version currently running on your BMC hardware
- 2. Upgrade OpenBMC to a version newer than 2.9.0 (such as 2.10.0 or later) which contains the fix for CVE-2021-39296
- 3. After upgrading, verify the IPMI authentication mechanism is working correctly
- 4. Test that the authentication bypass vulnerability is no longer present by attempting the documented attack vector with crafted IPMI messages
- 5. Ensure the BMC firmware update completes successfully and the system reboots properly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39296 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-39296 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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