CVE intelligence and bounded remediation

CVE-2021-3929 — A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU

High CVSS 8.2

A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU. This CVE is similar to CVE-2021-3750 and, just like it, when the reentrancy write triggers the reset function nvme_ctrl_reset(), data structs will be freed leading to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition or, potentially, executing arbitrary code within the context of the QEMU process on the host.

Severity
High
CVSS
8.2 (3.1)
Published
2022-08-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-416

Affected products

  • qemu / qemu
  • fedoraproject / fedora / 35
  • fedoraproject / fedora / 36

Matched remediation archetype

Use-after-free, double free, and expired resource use

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace ownership, references, callbacks, asynchronous tasks, and teardown paths around the affected object or resource.
  • Identify reachable inputs and timing or state transitions that can release the object while references remain.
  • Confirm affected builds, allocators, feature flags, architectures, and process privileges.

Remediate safely

  • Apply the maintained ownership or lifetime fix and rebuild all artifacts containing the affected native code.
  • Use explicit ownership, safe reference management, cancellation and join semantics, and idempotent teardown.
  • Add deterministic lifetime tests plus isolated sanitizer and concurrency coverage for shutdown and error paths.

Authoritative sources

Complete CVE record and remediation plan

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