What’s Vulnerable › Vulnerabilities
CVE-2021-3929
- Severity: high (CVSS 8.2 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.7% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2022-08-25 · updated 2026-06-17
- Weakness: CWE-416
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.
Affected products
- Fedoraproject Fedora: 35, 36
- QEMU: before 7.0.0 — fixed in 7.0.0
How to fix
Upgrade to a fixed version: QEMU 7.0.0. Check the vendor advisory for mitigations.
References
- https://access.redhat.com/security/cve/CVE-2021-3929
- https://bugzilla.redhat.com/show_bug.cgi?id=2020298
- https://gitlab.com/qemu-project/qemu/-/commit/736b01642d85be832385
- https://gitlab.com/qemu-project/qemu/-/issues/556
- https://gitlab.com/qemu-project/qemu/-/issues/782
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XHNN7QJCEQH7AQG5AQP2GEFAQE6K635I/
- https://access.redhat.com/security/cve/CVE-2021-3929
- https://bugzilla.redhat.com/show_bug.cgi?id=2020298
- https://gitlab.com/qemu-project/qemu/-/commit/736b01642d85be832385
- https://gitlab.com/qemu-project/qemu/-/issues/556
- https://gitlab.com/qemu-project/qemu/-/issues/782
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XHNN7QJCEQH7AQG5AQP2GEFAQE6K635I/
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