🛡️ CVE-2026-40209

🟡 CVSS 5.3 — Medium ✅ No Known Exploit CWE-772 NVD
5.3
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability low.

Weakness class

CVE-2026-40209 is classified as CWE-772: Missing Release of Resource. A resource is acquired but never released on some paths, depleting the pool over time.

Affected software

CVE-2026-40209 is recorded against 1 package.

  • unknown

Timeline and source

Published on 25 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

www.dnsdist.org

Details

Severity MEDIUM
CVSS Score 5.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE CWE-772
Public Exploit ✅ No
Source NVD
Published 2026-06-25
Updated 2026-08-11
Modified 2026-06-25
Fix URL N/A

Affected Packages

Software From version Fixed in
unknown — —

Similar Threats

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