Vulnerability · Published Aug 26, 2022 · Assigned by redhat
CVE-2021-3735
Medium 4.4
In plain English
A medium-severity security flaw in QEMU. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).
Severity (CVSS NVD)4.4Medium
Exploit odds (30 days)0.2%top 89.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
A deadlock issue was found in the AHCI controller device of QEMU. It occurs on a software reset (ahci_reset_port) while handling a host-to-device Register FIS (Frame Information Structure) packet from the guest. A privileged user inside the guest could use this flaw to hang the QEMU process on the host, resulting in a denial of service condition. The highest threat from this vulnerability is to system availability.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | qemu | no fix listed | DEBIAN-CVE-2021-3735 |
| Debian:13 | qemu | no fix listed | DEBIAN-CVE-2021-3735 |
| Debian:14 | qemu | no fix listed | DEBIAN-CVE-2021-3735 |
| Ubuntu:22.04:LTS | qemu | no fix listed | UBUNTU-CVE-2021-3735 |
| Ubuntu:24.04:LTS | qemu | no fix listed | UBUNTU-CVE-2021-3735 |
| Ubuntu:25.10 | qemu | no fix listed | UBUNTU-CVE-2021-3735 |
| Ubuntu:26.04:LTS | qemu | no fix listed | UBUNTU-CVE-2021-3735 |
| Ubuntu:26.10 | qemu | no fix listed | UBUNTU-CVE-2021-3735 |
| Ubuntu:26.04:LTS | qemu-hwe | no fix listed | UBUNTU-CVE-2021-3735 |
| Ubuntu:26.10 | qemu-hwe | no fix listed | UBUNTU-CVE-2021-3735 |
Affected products (as reported)
Weakness: CWE-667