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CVE-2026-40209

Denial of service via IXFR queries

Published: Jun 25, 2026Updated: Jun 25, 2026 Sources: CVE List NVDCWE-772
5.3MEDIUM
NVD MITRE
EPSS Score
0.3%
Top 78.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
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Weaknesses

CWE-772

Affected Products

PowerDNS
oss-project·DKaka powerdns authoritative, powerdns recursor, dnsdist
DNSdistOn-prem
Networking Infrastructure / dns-dhcp-ntp

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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References

https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html
dnsdist.org

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