5.3

CVE-2026-40211: powerdns dnsdist

CVSS: 5.3v3.1MediumDeferred
AliasesUBUNTU-CVE-2026-40211DEBIAN-CVE-2026-40211
Published 25-06-2026Last modified 25-06-2026
Open JSON

Vulnerability summary

CVE-2026-40211 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 · +0.40 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 can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.

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

+0.40 pp

From 0.30% 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