Denial of service via crafted TCP exchange
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-674.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA DNSdist (PowerDNS) Fixed in 1.9.10
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2025-30193
- 2026-10-03 Alias added: GHSA-4q3h-v92p-gchj
More PowerDNS vulnerabilities
- TI-2023-27571 Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related… CVSS 3.1HIGH 7.5
- TI-2023-27773 The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance… CVSS 3.1HIGH 7.5
- TI-2015-01678 The label decompression functionality in PowerDNS Recursor 3.5.x, 3.6.x before 3.6.3, and… CVSS 2.0HIGH 7.8
- TI-2021-14878 PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by… CVSS 3.1HIGH 7.5
- TI-2016-04703 PowerDNS (aka pdns) Authoritative Server before 3.4.10 does not properly handle a . CVSS 3.0HIGH 7.5
- TI-2018-12065 Out-of-bounds read in [UNKNOWN] pdns-recursor CVSS 3.0HIGH 7.5
Sources
- CVE-2025-30193 · CVE Program
- CVE-2025-30193 · NVD
- FIRST EPSS
- GHSA-4q3h-v92p-gchj · GitHub Advisory Database · CC BY 4.0
- CVE-2025-30193 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences