#VU63775 NULL pointer dereference in QEMU - CVE-2021-20196

Vulnerability identifier: #VU63775

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-2021-20196

CWE-ID: CWE-476

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 (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the floppy disk emulator of QEMU. A privileged guest can trigger a NULL pointer dereference error and cause a denial of service. 

Mitigation
Install update from vendor's website.

Vulnerable software versions

QEMU: 2.12.1 - 5.2.0

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External links
https://bugs.launchpad.net/qemu/+bug/1912780
https://www.openwall.com/lists/oss-security/2021/01/28/1
https://security.netapp.com/advisory/ntap-20210708-0004/
https://bugzilla.redhat.com/show_bug.cgi?id=1919210

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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.