CVE-2023-3255: Qemu: vnc: infinite loop in inflate_buffer() leads to denial of service

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-13 · updated 2026-06-17
Weakness: CWE-835

Description

A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. A wrong exit condition may lead to an infinite loop when inflating an attacker controlled zlib buffer in the `inflate_buffer` function. This could allow a remote authenticated client who is able to send a clipboard to the VNC server to trigger a denial of service.

Affected products

Fedoraproject Fedora: 38
QEMU: through 8.0.3
Red Hat Enterprise Linux: 8.0, 9.0

References

https://access.redhat.com/errata/RHSA-2024:2135
https://access.redhat.com/errata/RHSA-2024:2962
https://access.redhat.com/security/cve/CVE-2023-3255
https://bugzilla.redhat.com/show_bug.cgi?id=2218486
https://access.redhat.com/errata/RHSA-2024:2135
https://access.redhat.com/errata/RHSA-2024:2962
https://access.redhat.com/security/cve/CVE-2023-3255
https://bugzilla.redhat.com/show_bug.cgi?id=2218486
https://security.netapp.com/advisory/ntap-20231020-0008/

Get alerted when CVE-2023-3255 or the next vulnerability affects your stack