CVE-2023-6683: qemu Null Dereference — Fix

Description

A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. The qemu_clipboard_request() function can be reached before vnc_server_cut_text_caps() was called and had the chance to initialize the clipboard peer, leading to a NULL pointer dereference. This could allow a malicious authenticated VNC client to crash QEMU and trigger a denial of service.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
qemu	qemu	6.1.0 — 8.2.2
redhat	enterprise_linux	All
redhat	enterprise_linux	All

References

Advisories & Patches

https://bugzilla.redhat.com/show_bug.cgi?id=2254825 https://bugzilla.redhat.com/show_bug.cgi?id=2254825

Other References

https://access.redhat.com/errata/RHSA-2024:2135 https://access.redhat.com/errata/RHSA-2024:2962 https://access.redhat.com/security/cve/CVE-2023-6683 https://access.redhat.com/errata/RHSA-2024:2135 https://access.redhat.com/errata/RHSA-2024:2962 https://access.redhat.com/security/cve/CVE-2023-6683 https://security.netapp.com/advisory/ntap-20240223-0001/

Frequently Asked Questions

What is CVE-2023-6683? +

A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. The qemu_clipboard_request() function can be reached before vnc_server_cut_text_caps() was called and had the chance to initialize the clipboard peer, leading to a NULL pointer dereference. This could allow a malicious authenticated VNC client to crash QEMU and trigger a denial of service. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2023-6683? +

CVE-2023-6683 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2023-6683? +

CVE-2023-6683 affects products from qemu, redhat, specifically: enterprise_linux, qemu. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-6683? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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