Debian LinuxOperating system · Debian
CVE-2021-3545
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 · uneditedAn information disclosure vulnerability was found in the virtio vhost-user GPU device (vhost-user-gpu) of QEMU in versions up to and including 6.0. The flaw exists in virgl_cmd_get_capset_info() in contrib/vhost-user-gpu/virgl.c and could occur due to the read of uninitialized memory. A malicious guest could exploit this issue to leak memory from the host.
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 confidenceA memory disclosure vulnerability exists in QEMU's virtio vhost-user GPU device (vhost-user-gpu) where the function virgl_cmd_get_capset_info() in contrib/vhost-user-gpu/virgl.c reads uninitialized memory. A malicious guest can exploit this to leak host memory contents.
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
= 11.0<= 6.0.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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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Check installed QEMU versionRun 'qemu-system-x86_64 --version' or 'qemu --version' and compare the version number to the affected range <= 6.0.0Affected if QEMU version is 6.0.0 or lower (or if version cannot be determined but the package is from Debian 11)
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Verify vhost-user-gpu binary presenceCheck if the vhost-user-gpu binary exists on the system using 'which vhost-user-gpu' or by searching in common paths like /usr/bin/vhost-user-gpuAffected if The vhost-user-gpu binary is present on the system
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Check for vulnerable virgl renderer librarySearch for the libvirglrenderer library or virglrenderer package using your package manager (dpkg -l | grep virgl or rpm -qa | grep virgl)Affected if The virglrenderer library is installed, as this component provides the virgl_cmd_get_capset_info() function
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Inspect VM configurations for virtio-gpu usageReview VM configuration files (typically in /etc/libvirt/qemu/ or /var/lib/libvirt/images/) for any <graphics> or <video> device definitions using virtio-gpu with vhostuser or virgl enabledAffected if Any VM is configured to use virtio-gpu with the vhost-user or virglgl acceleration enabled
A system is affected if QEMU version is 6.0.0 or lower AND the vhost-user-gpu component or virglrenderer library is present and actively used by any virtual machine.
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 dataUpgrade QEMU to version 6.1 or later which contains the fix for proper memory initialization in the affected function.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 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 $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3545 — 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-2021-3545 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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