TI-2026-29020 Aliases CVE-2026-40209 GHSA-c5m7-ppm5-wp5g

Denial of service via IXFR queries

LOW 31CWE-772Published 2026-06-25 · Updated 2026-06-25

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-772.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.007 53rd percentileScored 2026-11-07

Fix Fixed DNSdist (PowerDNS): 1.9.15, 2.0.7

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
PowerDNS	DNSdist	1.9.0 to before 1.9.15; 2.0.0 to before 2.0.7	1.9.15, 2.0.7	Patch available	CNA

DNSdist VendorPowerDNS Affected 1.9.0 to before 1.9.15; 2.0.0 to before 2.0.7 Fixed in 1.9.15, 2.0.7 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:powerdns:dnsdist::::::::	—	—	PowerDNS

cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:* Versions — — ·PowerDNS

Remediation

Fix · CNA DNSdist (PowerDNS) Fixed in 1.9.15, 2.0.7

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-06-25
PowerDNS DNSdist 1.9.15, 2.0.7
6 records Highest priority Priority LOW 6 LOW
Other records, highest priority first
- TI-2026-29022 Denial of service via crafted DoH3 queriesPriority LOW 31
- TI-2026-29021 Out-of-bounds read in SetMacAddrActionPriority LOW 23
- TI-2026-29019 Denial of service via DoH3 queriesPriority LOW 18
Show all 6 records →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product

Red Hat

Timeline

2026-10-02 Threatist record created from CVE-2026-40209
2026-10-03 Alias added: GHSA-c5m7-ppm5-wp5g

References

Other 1

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

TI-2023-27571 Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related… CVSS 3.1HIGH 7.5
TI-2023-27773 The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance… CVSS 3.1HIGH 7.5
TI-2015-01678 The label decompression functionality in PowerDNS Recursor 3.5.x, 3.6.x before 3.6.3, and… CVSS 2.0HIGH 7.8
TI-2021-14878 PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by… CVSS 3.1HIGH 7.5
TI-2016-04703 PowerDNS (aka pdns) Authoritative Server before 3.4.10 does not properly handle a . CVSS 3.0HIGH 7.5
TI-2018-12065 Out-of-bounds read in [UNKNOWN] pdns-recursor CVSS 3.0HIGH 7.5

See all 130 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences