CVE-2021-3929 Use after free in QEMU

What is CVE-2021-3929?

CVE-2021-3929 is a high-severity use after free vulnerability in Fedoraproject Fedora, published on 25 Aug 2022. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-416

Which versions are affected by CVE-2021-3929?

It affects 2 products.

Products include Fedoraproject Fedora, Qemu Qemu.

How do I fix CVE-2021-3929?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2021-3929 being exploited?

There is no known exploitation of CVE-2021-3929 in the wild and no public exploit code.

Public exploit code: 2 proofs of concept on GitHub.

Other vulnerabilities in Fedoraproject Fedora

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• CVE-2021-39226 Grafana Authentication Bypass Exploited Critical 9.8
• CVE-2019-5544 VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Exploited Critical 9.8
• CVE-2024-4947 Google Chromium V8 Type Confusion Exploited Critical 9.6
• CVE-2024-4671 Google Chromium Visuals Use-After-Free Exploited Critical 9.6

All Fedoraproject Fedora vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-10721, AZL-35152, DEBIAN-CVE-2021-3929, GHSA-h66w-323g-4q62, OESA-2022-1733, UBUNTU-CVE-2021-3929 and 1 more.