Vulnerability identifier: #VU80015

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-3354

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
QEMU
Client/Desktop applications / Virtualization software

Vendor: QEMU

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in NULL pointer dereference and denial of service.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

QEMU: All versions

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=2216478
http://access.redhat.com/security/cve/CVE-2023-3354
http://lists.nongnu.org/archive/html/qemu-devel/2023-07/msg01014.html
http://lists.nongnu.org/archive/html/qemu-devel/2023-07/msg02668.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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