CVE-2021-3735
A deadlock issue was found in the AHCI controller device of QEMU. It occurs on a software reset (ahci_reset_port) while handling a…
- Published
- Updated
- Reserved
- Assigned by
- redhat
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.
Timeline
ID reserved
By redhat
- 12 months later
· 12 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium4.4 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.21% · top 89% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.4.
Weakness
Affected products
QEMU
- affected Not Known
References (4)
- https://bugzilla.redhat.com/show_bug.cgi?id=1997184 (opens in a new tab)x_refsource_MISCx_transferred
- https://access.redhat.com/security/cve/CVE-2021-3735 (opens in a new tab)x_refsource_MISCx_transferred
- https://security-tracker.debian.org/tracker/CVE-2021-3735 (opens in a new tab)x_refsource_MISCx_transferred
- https://security.netapp.com/advisory/ntap-20250228-0009/ (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-3735)Record last updated .