CVE-2021-38918
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 · uneditedIBM PowerVM Hypervisor FW860, FW940, FW950, and FW1010, through a specific sequence of VM management operations could lead to a violation of the isolation between peer VMs. IBM X-Force ID: 210019.
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 confidenceIBM PowerVM hypervisor versions FW860 through FW1010 contain a logic flaw where a specific sequence of VM management operations can violate isolation between peer VMs running on the same hypervisor. This represents a VM escape vulnerability allowing a malicious or compromised VM to potentially access or affect another VM on the same hypervisor host.
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= fw860= fw940= fw950= fw1010CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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 PowerVM hypervisor firmware versionUse the PowerVM management interface (such as HMC or IVM) to retrieve the current firmware version. Look for the hypervisor firmware level in the system information or use the relevant command to query the partition firmware version.Affected if The installed firmware version is FW860, FW940, FW950, or FW1010 exactly as listed in the affected versions.
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Confirm multiple VMs exist on the same hypervisorList all partitions or virtual machines running on the hypervisor host using the HMC or IVM interface. Count the number of active VMs on the same physical hypervisor system.Affected if More than one VM (peer VMs) is running on the same hypervisor host; the flaw requires a peer VM to be present for the isolation violation to be exploitable.
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Verify VM placement and shared processor pool configurationInspect the VM configuration to determine if they share the same processor pool or resources. Review the placement of VMs on the same LPAR or hypervisor node.Affected if VMs are configured to run on the same hypervisor host with shared resources, creating the conditions for the attack sequence to target peer VMs.
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Review recent VM management operationsAudit logs of VM lifecycle operations such as live migration, VM creation, deletion, or resource reallocation performed on the hypervisor.Affected if A specific sequence of VM management operations has been performed on the hypervisor host, as the vulnerability requires this operational sequence to trigger the isolation flaw.
You are affected if your PowerVM hypervisor firmware version is exactly FW860, FW940, FW950, or FW1010 and you have multiple VMs running on the same hypervisor host where the attack sequence could be triggered.
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.
From vendor dataApply IBM-supplied firmware updates for the affected PowerVM versions (FW860, FW940, FW950, FW1010). Review VM management operational procedures to understand the attack vector until patches are applied.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $10,240.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-38918 — 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-2021-38918 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data