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KvmtoolApplication · Kvmtool Project

CVE-2021-45464

HIGH · 8.8 CVSS v3.1 Published 2023-04-15
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
90/100
Remediation priority · Urgent
Public exploit Zero-click Patch available

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 · unedited
kvmtool through 39181fc allows an out-of-bounds write, related to virtio/balloon.c and virtio/pci.c. This allows a guest OS user to execute arbitrary code on the host machine.

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
How this class of weakness works · CWE-787

The program writes past the bounds of a buffer, overwriting adjacent memory an attacker can turn to their advantage. Crafted input can overwrite control data and redirect execution. Remediation is validating every index and length before a write, plus modern memory-safety mitigations.

General guidance for the out-of-bounds write class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
KvmtoolApplication
Affected:all versions

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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 · scoped
Patch available Apply the vendor patch
Vendor patch git.kernel.org →
Recommended fix High confidence

A version/commit after 39181fc6429f4e9e71473284940e35857b42772a (the fixed commit itself or later)

  1. 1. Identify the current kvmtool version in use by running `git log --oneline` or checking the build/version information
  2. 2. Navigate to the kvmtool repository: https://git.kernel.org/pub/scm/linux/kernel/git/will/kvmtool.git
  3. 3. Check if the fix commit 39181fc6429f4e9e71473284940e35857b42772a is present in your current build
  4. 4. If not present, fetch the latest changes from the kvmtool repository: `git fetch origin`
  5. 5. Apply the fix by pulling the latest code or cherry-picking the specific commit: `git cherry-pick 39181fc6429f4e9e71473284940e35857b42772a`
  6. 6. Rebuild kvmtool with the fix applied
  7. 7. Verify the fix is applied by checking the commit appears in the history: `git log --oneline | grep 39181fc`
  8. 8. Redeploy the updated kvmtool binary to all affected hosts

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-45464 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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