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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| PowerDNS | DNSdist | 1.9.0 – < 1.9.15, 2.0.0 – < 2.0.7 | 1.9.15 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | dnsdist | 2.1.0-1 | — |
| Debian 13 | dnsdist | 1.9.15-0+deb13u1 | — |
| Debian 12 | dnsdist | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | dnsdist | No fix yet | — |
| Ubuntu 26.04 LTS | dnsdist | No fix yet | — |
| Ubuntu 25.10 | dnsdist | No fix yet | — |
| Ubuntu 16.04 LTS | dnsdist | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | dnsdist | No fix yet | — |
| Ubuntu Pro 22.04 LTS | dnsdist | No fix yet | — |
| Ubuntu Pro 20.04 LTS | dnsdist | No fix yet | — |
| Ubuntu Pro 18.04 LTS | dnsdist | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | dnsdist | 1.9.15-160000.1.1 | SUSE-SU-2026:23146-1, SUSE-SU-2026:23123-1 |
| SLES 16.0 | dnsdist | 1.9.15-160000.1.1 | SUSE-SU-2026:23146-1, SUSE-SU-2026:23123-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dnsdist | 2.0.7-1.1 | openSUSE-SU-2026:11411-1 |
| openSUSE Leap 16.0 | dnsdist | 1.9.15-160000.1.1 | openSUSE-SU-2026:21533-1 |
Advisories 5
- WID-SEC-2026-2091 PowerDNS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 16, 2026
- SUSE-SU-2026:23146-1 Security update for dnsdist SUSE / openSUSE Security Updates · Aug 14, 2026
- SUSE-SU-2026:23123-1 Security update for dnsdist SUSE / openSUSE Security Updates · Aug 14, 2026
- openSUSE-SU-2026:21533-1 Security update for dnsdist SUSE / openSUSE Security Updates · Aug 6, 2026
- openSUSE-SU-2026:11411-1 dnsdist-2.0.7-1.1 on GA media SUSE / openSUSE Security Updates · Aug 1, 2026