Debian LinuxOperating system · Debian
CVE-2015-8744
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 · uneditedQEMU (aka Quick Emulator) built with a VMWARE VMXNET3 paravirtual NIC emulator support is vulnerable to crash issue. It occurs when a guest sends a Layer-2 packet smaller than 22 bytes. A privileged (CAP_SYS_RAWIO) guest user could use this flaw to crash the QEMU process instance resulting in DoS.
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 confidenceQEMU built with the VMWARE VMXNET3 paravirtual NIC emulator contains a vulnerability where processing a Layer-2 packet smaller than 22 bytes triggers a crash. A guest user with CAP_SYS_RAWIO privileges can exploit this to terminate the QEMU process instance, causing a denial of service.
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
Debian LinuxOperating system
= 8.0<= 2.4.1CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 QEMU versionRun 'qemu-system-x86_64 --version' or check installed package version with 'dpkg -l qemu-system-x86' or 'rpm -q qemu-kvm'Affected if The version is 2.4.1 or lower, or the package version indicates QEMU <= 2.4.1
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Locate VMs using VMXNET3 NICInspect VM configuration files (e.g., libvirt XML via 'virsh dumpxml <vmname>'), looking for '<model type='vmxnet3'/>' or similar NIC model definitionsAffected if Any VM definition shows a vmxnet3 paravirtual NIC adapter is configured
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Verify VMXNET3 driver is loaded or activeWithin a running guest, check if the vmxnet3 driver is loaded with 'lsmod | grep vmxnet' or check network adapter detailsAffected if The vmxnet3 network driver is active in a guest running on the affected QEMU version
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Check guest privilege levelInside the guest, verify if the user has CAP_SYS_RAWIO capability by checking process capabilities with 'getcap' or reviewing user/group permissionsAffected if The guest user or process possesses CAP_SYS_RAWIO privileges, making exploitation possible
You are affected if QEMU version is 2.4.1 or lower AND a VM is configured with a VMXNET3 paravirtual NIC, as the crash occurs when processing Layer-2 packets smaller than 22 bytes.
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 dataUpdate QEMU to a version that includes the fix for proper bounds checking on small packets in the VMXNET3 driver. As a workaround, restrict guest privileges and implement network filtering to block abnormally small Layer-2 packets.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-8744 — 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-2015-8744 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
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