What’s Vulnerable › Vulnerabilities
CVE-2023-3354: Improper i/o watch removal in tls handshake can lead to remote unauthenticated denial of service
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.6% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2023-07-11 · updated 2026-06-17
- Weakness: CWE-476
Description
A flaw was found 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 a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.
Affected products
- Fedoraproject Fedora: 38
- QEMU: before 8.1.0; 8.1.0-rc0, 8.1.0-rc1 — fixed in 8.1.0
- Red Hat Enterprise Linux: 7.0, 8.0, 9.0
- nova_libvirt container provided by the Red Hat OpenStack Platform: 13.0
How to fix
Upgrade to a fixed version: QEMU 8.1.0. Check the vendor advisory for mitigations.
References
- https://access.redhat.com/security/cve/CVE-2023-3354
- https://bugzilla.redhat.com/show_bug.cgi?id=2216478
- https://lists.debian.org/debian-lts-announce/2024/03/msg00012.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MURWGXDIF2WTDXV36T6HFJDBL632AO7R/
- https://access.redhat.com/security/cve/CVE-2023-3354
- https://bugzilla.redhat.com/show_bug.cgi?id=2216478
- https://lists.debian.org/debian-lts-announce/2024/03/msg00012.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MURWGXDIF2WTDXV36T6HFJDBL632AO7R/
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