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HyperkitApplication · Mobyproject

CVE-2021-32845

HIGH · 7.8 CVSS v3.1 Published 2023-02-17
Fix available
A fix is available. Upgrade to after 0.20210107 or later.
See remediation →
80/100
Remediation priority · High
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
HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0.20210107 and prior of HyperKit, the implementation of `qnotify` at `pci_vtrnd_notify` fails to check the return value of `vq_getchain`. This leads to `struct iovec iov;` being uninitialized and used to read memory in `len = (int) read(sc->vrsc_fd, iov.iov_base, iov.iov_len);` when an attacker is able to make `vq_getchain` fail. This issue may lead to a guest crashing the host causing a denial of service and, under certain circumstance, memory corruption. This issue is fixed in commit 41272a980197917df8e58ff90642d14dec8fe948.

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-908

Memory or a resource is used before it has been initialised, so its contents are whatever happened to be there — sometimes leaking earlier data, sometimes values an attacker can influence. Behaviour becomes unpredictable and occasionally exploitable. Remediation is initialising every resource before use and ensuring initialisation happens on all code paths.

General guidance for the use of uninitialized resource 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
HyperkitApplication
Affected:<= 0.20210107

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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
Upgrade available Upgrade to a release after 0.20210107
Vendor patch github.com →
Recommended fix High confidence

Latest stable HyperKit release after 0.20210107 (verify the release includes commit 41272a980197917df8e58ff90642d14dec8fe948)

  1. 1. Identify the current HyperKit version in use by checking the binary or build information
  2. 2. Navigate to the official HyperKit GitHub releases page at https://github.com/moby/hyperkit/releases
  3. 3. Locate and download a release version newer than 0.20210107 that includes the fix from commit 41272a980197917df8e58ff90642d14dec8fe948
  4. 4. Before deploying in production, test the new version in a staging environment to ensure compatibility with existing workloads
  5. 5. Stop any running virtual machines or services using the current HyperKit version
  6. 6. Replace the existing HyperKit binary with the updated version
  7. 7. Restart the hypervisor and verify that virtual machines启动 successfully
  8. 8. Monitor system logs to confirm the vulnerability is no longer present and no crashes occur
Caveat Minor: Review release notes for any API or compatibility changes between versions; the fix is a bug fix and should not introduce breaking changes

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

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $1,950. Get the upgrade done

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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-2021-32845 in production — separate from our analysis above.

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What this is

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