CVE-2021-3929: fedoraproject fedora Use After Free

Vulnerability summary

CVE-2021-3929 is a high (CVSS 8.2) Use After Free vulnerability in fedoraproject fedora. EPSS estimates a 0.68% chance of exploitation in the next 30 days, higher than 52.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 25-08-2022
   PublishedVulnerability first disclosed.
2. 28-02-2025
   Last modifiedVulnerability information updated.

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.

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.