CVE-2023-6683: Qemu: vnc: null pointer dereference in qemu_clipboard_request()
Vulnerability summary
CVE-2023-6683 is a medium (CVSS 6.5) NULL Pointer Dereference vulnerability in qemu. EPSS estimates a 1.26% chance of exploitation in the next 30 days, higher than 69.6% of scored vulnerabilities.
Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 7 · Related 4Timeline
- 12-01-2024PublishedVulnerability first disclosed.
- 25-02-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
1.26%
Chance of exploitation in the next 30 days
Percentile
70%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.26% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- qemu< 1:7.2+dfsg-7+deb12u4 | < 1:8.2.0+ds-5
Qemu1 product
- qemu≥ 6.1.0, < 8.2.2
Redhat1 product
- enterprise_linux8.0 | 9.0
Ubuntu1 product
- qemu< 1:6.2+dfsg-2ubuntu6.22
4 vendors · 4 products
