#VU63776 Integer overflow in QEMU - CVE-2021-20203

Vulnerability identifier: #VU63776

Vulnerability risk: Low

CVSSv4.0: 1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-20203

CWE-ID: CWE-190

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
QEMU
Client/Desktop applications / Virtualization software

Vendor: QEMU

Description

The vulnerability allows a local user to perform a denial of service attack.

The vulnerability exists due to integer overflow in the vmxnet3 NIC emulator of the QEMU. A privileged guest user can pass invalid values for the rx/tx queue size or other NIC parameters and perform a denial of service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

QEMU: 2.12.1 - 5.2.0

---

External links
https://bugs.launchpad.net/qemu/+bug/1913873
https://bugzilla.redhat.com/show_bug.cgi?id=1922441
https://lists.debian.org/debian-lts-announce/2021/04/msg00009.html

---

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.