5.3

CVE-2026-40209: powerdns dnsdist

CVSS: 5.3v3.1MediumDeferred
AliasesUBUNTU-CVE-2026-40209DEBIAN-CVE-2026-40209
Published 25-06-2026Last modified 25-06-2026
Open JSON

Vulnerability summary

CVE-2026-40209 is a medium (CVSS 5.3) vulnerability in powerdns dnsdist. EPSS estimates a 0.70% chance of exploitation in the next 30 days, higher than 52.3% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.70%
0%100%
Low · +0.41 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 4
OPENSUSE-SU-2026:11411-1OPENSUSE-SU-2026:21533-1SUSE-SU-2026:23123-1SUSE-SU-2026:23146-1

Timeline

  1. 25-06-2026
    PublishedVulnerability first disclosed.
  2. 25-06-2026
    Last modifiedVulnerability information updated.

Description

An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.70%

Chance of exploitation in the next 30 days

Percentile

52%

Versus all other CVEs

30-day change

+0.41 pp

From 0.29% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.70%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • dnsdistAll versions (No fix recorded) | < 1.9.15-0+deb13u1 | < 2.1.0-1
Powerdns1 product
  • dnsdist≥ 1.9.0, < 1.9.15 | ≥ 2.0.0, < 2.0.7
Ubuntu1 product
  • dnsdistAll versions (No fix recorded)

3 vendors · 3 products

References

5 links