CVE-2024-21961
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 · uneditedImproper restriction of operations within the bounds of a memory buffer in PCIe® Link could allow an attacker with access to a guest virtual machine to potentially perform a denial of service attack against the host resulting in loss of availability.
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 · high confidenceImproper memory buffer boundary checking in the PCIe Link layer of a virtualization platform allows a guest virtual machine attacker to trigger buffer overflow operations, potentially causing a denial of service on the host system.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- High
- Privileges
- Low
- Authentication
- X
- User interaction
- None
- Scope
- X
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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 your virtualization platformDetermine which hypervisor runs on the host system (e.g., VMware ESXi, KVM/QEMU, Xen, Hyper-V). Use commands like 'vmware -v', 'xm info', or check system documentation.Affected if The vulnerability exists in the PCIe Link layer of an unspecified virtualization platform - you must first confirm which product is in use.
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Determine the hypervisor versionRun the platform-specific version command (e.g., 'vmware -v' for VMware, 'qemu-system-x86_64 --version' for KVM, or check host system info). Compare this version to vendor security advisories for CVE-2024-21961.Affected if If your installed version matches an unpatched version listed in the vendor advisory for this CVE, your hypervisor is potentially vulnerable.
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Verify if PCIe device passthrough is enabledCheck hypervisor configuration for PCIe passthrough settings. For KVM: look for 'iommu' in kernel boot parameters or libvirt XML 'hostdev' entries. For VMware: check for 'passthrough' config in vCenter/ESXi. For Xen: check xl config for 'pci' assignments.Affected if The PCIe Link layer vulnerability is exploitable when PCIe devices can be directly assigned to or accessed by guest VMs. If passthrough is enabled and the hypervisor version is unpatched, you are affected.
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List any assigned PCIe devices to VMsQuery the hypervisor for VMs with directly assigned PCIe devices. For KVM: 'virsh dumpxml <vmname>' and look for '<hostdev>' entries with 'type=pci'. For VMware: check VM hardware settings for PCIe passthrough devices.Affected if If any VMs have PCIe devices directly assigned and the hypervisor is unpatched, the guest attacker could potentially trigger the buffer overflow in the PCIe Link layer.
Your environment is affected if the virtualization platform is an unpatched version matching the CVE and PCIe device passthrough or direct assignment to VMs is enabled, exposing the PCIe Link layer to guest VM attackers.
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 vendor-supplied security patches for the hypervisor PCIe subsystem; consider VM isolation or access restrictions until patching is complete.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-21961 — 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-2024-21961 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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- Version or environment caveats, and links to real fixes
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