Integer overflow in dnsdist - CVE-2026-33596
Published: April 23, 2026
Vulnerability identifier: #VU126950
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-33596
CWE-ID: CWE-190
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vendor: PowerDNS.COM B.V.
Affected software:
dnsdist
dnsdist
Detailed vulnerability description
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.
How to mitigate CVE-2026-33596
Install security update from vendor's website.