Integer overflow in dnsdist - CVE-2026-33596
Published: April 23, 2026
Vulnerability identifier: #VU126950
CSH Severity: Low
CVSS v4: 2.3 [CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-33596
CWE-ID: CWE-190
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to integer overflow in TCP backend stream id handling when processing perfectly timed queries routed to a TCP-only or DoT backend. A remote attacker can send a flood of perfectly timed queries to cause a denial of service.
Exploitation requires queries to be routed to a TCP-only or DNS over TLS backend.
Affected software
dnsdist
Debian Linux
Fedora
dnsdist (Debian package)
dnsdist
Debian Linux
Fedora
dnsdist (Debian package)
dnsdist
How to mitigate CVE-2026-33596
Install security update from vendor's website.
dnsdist - addressed in versions 1.9.13, 2.0.4
dnsdist (Debian package) - update to 1.9.14-0+deb13u1
dnsdist - update to 2.0.6-1.el10_2
dnsdist (Debian package) - update to 1.9.14-0+deb13u1
dnsdist - update to 2.0.6-1.el10_2