CVE-2025-30193

Publication date 20 May 2025

Last updated 12 February 2026

Ubuntu priority

Cvss 3 Severity Score

Description

In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single, incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service. The remedy is: upgrade to the patched 1.9.10 version. A workaround is to restrict the maximum number of queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection setting. We would like to thank Renaud Allard for bringing this issue to our attention.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
dnsdist	25.10 questing	Not affected
	25.04 plucky	Ignored end of life, was needs-triage
	24.10 oracular	Ignored end of life, was needs-triage
	24.04 LTS noble	Fixed 1.8.3-2ubuntu0.1~esm1
	22.04 LTS jammy	Fixed 1.6.1-1ubuntu0.1~esm2
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected

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Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-8037-1
DNSdist vulnerabilities
12 February 2026