Input validation error in dnsdist - CVE-2026-33597
Published: April 23, 2026
Vulnerability identifier: #VU126949
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/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-2026-33597
CWE-ID: CWE-20
Exploitation vector: Remote access
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 improper input validation in the PRSD detection algorithm when processing a crafted query containing an invalid DNS label. A remote attacker can send a crafted query to cause a denial of service.
Exploitation affects PRSD detection executed via DynBlockRulesGroup:setSuffixMatchRule or DynBlockRulesGroup:setSuffixMatchRuleFFI.
How to mitigate CVE-2026-33597
Install security update from vendor's website.