CVE-2025-30193 Denial of service via crafted TCP exchange
An attacker can cause a denial of service by exhausting the stack via crafted TCP exchanges when unlimited queries are allowed on a single connection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-30193?
CVE-2025-30193 is a high-severity denial of service vulnerability in PowerDNS DNSdist, published on 20 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-674
Which versions are affected by CVE-2025-30193?
Linux distribution packages (14)
dnsdist SUSE:Enterprise Storage 7.1 | All versions | 1.8.0-150100.3.8.1 |
dnsdist SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise Module for Basesystem 15 SP6 | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise Server 15 SP3-LTSS | All versions | 1.8.0-150100.3.8.1 |
dnsdist SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Manager Proxy 4.3 | All versions | 1.8.0-150400.9.6.1 |
dnsdist SUSE:Manager Server 4.3 | All versions | 1.8.0-150400.9.6.1 |
dnsdist openSUSE:Leap 15.6 | All versions | 1.8.0-150400.9.6.1 |
How do I fix CVE-2025-30193?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-30193 being exploited?
There is no known exploitation of CVE-2025-30193 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2025-30193, GHSA-4q3h-v92p-gchj, SUSE-SU-2025:01745-1, SUSE-SU-2025:01792-1, UBUNTU-CVE-2025-30193.