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VulnerabilityPublished

CVE-2026-40211: PowerDNS DNSdist · Unthrottled Resource Allocation

Affects PowerDNS DNSdistSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 2.0.7 or 1.9.15 when convenient.

Data as of 5 Nov 2026, 23:24 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.0.7, 1.9.15
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

What to do

Upgrade DNSdist and dnsdist to 2.0.7 or 1.9.15.

Affected software

ProductAffectedFixed in
PowerDNSDNSdistAffected
  • >=2.0.0 <2.0.7
Fixed in
  • 2.0.7
PowerDNSDNSdistAffected
  • >=1.9.0 <1.9.15
Fixed in
  • 1.9.15
GitHubdnsdistpkg:github/dnsdistOther threatsAffected
  • >=1.9.0 <1.9.15
  • >=2.0.0 <2.0.7
Fixed in
  • 1.9.15
  • 2.0.7

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, consider limiting the number of concurrent DoH3 streams or applying resource usage controls if possible.

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.

References

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