🛡️ CVE-2026-40209 on Ubuntu — dnsdist

⚪ Unknown ✅ No Known Exploit OSV
N/A
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.

Distribution advisory

This page covers CVE-2026-40209 as tracked by Ubuntu, for the package dnsdist. No fixed version has been recorded for this distribution yet.

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.

Affected software and timeline

Affected software: dnsdist. Published on 25 June 2026 and last revised on 29 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
www.dnsdist.org (Report)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-25
Updated 2026-08-11
Modified 2026-06-29
Fix URL N/A

Affected Packages

Software From version Fixed in
dnsdist — —

Similar Threats

Vulnerability Monitoring

Track new vulnerabilities in dnsdist

UBUNTU-CVE-2026-40209 is rated CVSS 5.3 Medium. BotEraser monitors your WordPress installation and notifies you when software you use appears in our vulnerability database.

Set Up Free Alerts →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

More UBUNTU CVE 2026 advisories

Part of UBUNTU CVE 2026 in the advisory index.