PowerDNS Security Advisory 2025-05 for DNSdist: Denial of service via crafted DoH exchangeΒΆ

  • CVE: CVE-2025-30187
  • Date: 2025-09-18T12:00:00+02:00
  • Discovery date: 2025-08-26T00:00:00+02:00
  • Affects: PowerDNS DNSdist from 1.9.0 to 1.9.10, 2.0.0
  • Not affected: PowerDNS DNSdist < 1.9.0, 1.9.11, 2.0.1
  • Severity: Low
  • Impact: Denial of service
  • Exploit: This problem can be triggered by an attacker crafting a DoH exchange
  • Risk of system compromise: None
  • Solution: Upgrade to patched version or use the h2o provider
  • CWE: CWE-835
  • CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
  • Last affected: 1.9.10,2.0.0
  • First fixed: 1.9.11,2.0.1
  • Internal ID: 308

In some circumstances, when DNSdist is configured to use the nghttp2 library to process incoming DNS over HTTPS queries, an attacker might be able to cause a denial of service by crafting a DoH exchange that triggers an unbounded I/O read loop, causing an unexpected consumption of CPU resources. The offending code was introduced in DNSdist 1.9.0-alpha1 so previous versions are not affected.

CVSS Score: 3.7

The remedy is: upgrade to a patched version, or switch to the h2o provider.