CVE-2021-3748
A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non…
- Published
- Updated
- Reserved
- Assigned by
- redhat
Description
A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.
Timeline
ID reserved
By redhat
- 7 months later
· 7 months later
Published
- 2 years later
· 2 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 | High7.5 | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.52% · top 55% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
QEMU (virtio-net)
- affected Affects qemu v0.10.0 and above, Fixed In – v6.2.0-rc0 and above.
References (8)
- https://bugzilla.redhat.com/show_bug.cgi?id=1998514 (opens in a new tab)x_refsource_MISCx_transferred
- https://ubuntu.com/security/CVE-2021-3748 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/qemu/qemu/commit/bedd7e93d01961fcb16a97ae45d93acf357e11f6 (opens in a new tab)x_refsource_MISCx_transferred
- https://lists.nongnu.org/archive/html/qemu-devel/2021-09/msg00388.html (opens in a new tab)x_refsource_MISCx_transferred
- [debian-lts-announce] 20220404 [SECURITY] [DLA 2970-1] qemu security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://security.netapp.com/advisory/ntap-20220425-0004/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- GLSA-202208-27 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- [debian-lts-announce] 20220905 [SECURITY] [DLA 3099-1] qemu security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
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-2021-3748)Record last updated .