CVE-2026-5950
Fixed in a distro release EPSS <1%CVSS 5.3
An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions. This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
Products: ISC BIND 9
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine:v3.20 | bind | 9.18.49-r0 |
| Alpine:v3.21 | bind | 9.18.49-r0 |
| Alpine:v3.22 | bind | 9.20.23-r0 |
| Alpine:v3.23 | bind | 9.20.23-r0 |
| Alpine:v3.24 | bind | 9.20.23-r0 |
| Debian:12 | bind9 | 1:9.18.49-1~deb12u2 |
| Debian:13 | bind9 | 1:9.20.23-1~deb13u1 |
| Debian:14 | bind9 | 1:9.20.23-1 |
| Red Hat:hummingbird:1 | bind | 0:9.18.49-1.hum1 |
| Red Hat:hummingbird:1 | bind-chroot | 0:9.18.49-1.hum1 |
| Red Hat:hummingbird:1 | bind-devel | 0:9.18.49-1.hum1 |
| Red Hat:hummingbird:1 | bind-dnssec-utils | 0:9.18.49-1.hum1 |
| Red Hat:hummingbird:1 | bind-doc | 0:9.18.49-1.hum1 |
| Red Hat:hummingbird:1 | bind-libs | 0:9.18.49-1.hum1 |
| Red Hat:hummingbird:1 | bind-utils | 0:9.18.49-1.hum1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | bind | 9.20.23-150700.3.25.1 |
| SUSE:Linux Enterprise Module for Server Applications 15 SP7 | bind | 9.20.23-150700.3.25.1 |
| SUSE:Linux Enterprise Server 15 SP6-LTSS | bind | 9.18.49-150600.3.26.1 |
| SUSE:Linux Enterprise Server 16.0 | bind | 9.20.23-160000.1.1 |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | bind | 9.18.49-150600.3.26.1 |
| SUSE:Linux Enterprise Server for SAP applications 16.0 | bind | 9.20.23-160000.1.1 |
| Ubuntu:18.04:LTS | isc-dhcp | no fix |
| Ubuntu:20.04:LTS | bind9-libs | no fix |
| Ubuntu:22.04:LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.4 |
| Ubuntu:22.04:LTS | bind9-libs | no fix |
| Ubuntu:24.04:LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.5 |
| Ubuntu:24.04:LTS | isc-dhcp | no fix |
| Ubuntu:25.10 | bind9 | 1:9.20.11-1ubuntu2.4 |
| Ubuntu:25.10 | isc-dhcp | no fix |
| Ubuntu:26.04:LTS | bind9 | 1:9.20.18-1ubuntu2.1 |
| Ubuntu:26.04:LTS | isc-dhcp | no fix |
| openSUSE:Leap 16.0 | bind | 9.20.23-160000.1.1 |
| openSUSE:Tumbleweed | bind | 9.20.23-1.1 |