How severe is CVE-2021-3929?

CVE-2021-3929 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-3929 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3929?

CVE-2021-3929 primarily affects Qemu. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3929?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-3929 published?

CVE-2021-3929 was published on 2022-08-25 and last updated on 2026-06-17.

CVE-2021-3929

CVE-2021-3929 is a high-severity vulnerability in Qemu with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: High (CVSS 3.x base score 8.2)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Qemu
Published: 2022-08-25
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-3929?: 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.
How severe is CVE-2021-3929?: CVE-2021-3929 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-3929 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3929?: CVE-2021-3929 primarily affects Qemu. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3929?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-3929 published?: CVE-2021-3929 was published on 2022-08-25 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*

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