CVE-2026-3591
Fixed in a distro release EPSS <1%CVSS 5.4
A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure. This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1. BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.
Products: ISC BIND 9
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine:v3.22 | bind | 9.20.21-r0 |
| Alpine:v3.23 | bind | 9.20.21-r0 |
| Alpine:v3.24 | bind | 9.20.21-r0 |
| Debian:13 | bind9 | 1:9.20.21-1~deb13u1 |
| Debian:14 | bind9 | 1:9.20.21-1 |
| Red Hat:hummingbird:1 | bind | 0:9.18.48-1.hum1 |
| Red Hat:hummingbird:1 | bind-chroot | 0:9.18.48-1.hum1 |
| Red Hat:hummingbird:1 | bind-devel | 0:9.18.48-1.hum1 |
| Red Hat:hummingbird:1 | bind-dnssec-utils | 0:9.18.48-1.hum1 |
| Red Hat:hummingbird:1 | bind-doc | 0:9.18.48-1.hum1 |
| Red Hat:hummingbird:1 | bind-libs | 0:9.18.48-1.hum1 |
| Red Hat:hummingbird:1 | bind-utils | 0:9.18.48-1.hum1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | bind | 9.20.21-150700.3.18.1 |
| SUSE:Linux Enterprise Module for Server Applications 15 SP7 | bind | 9.20.21-150700.3.18.1 |
| SUSE:Linux Enterprise Server 16.0 | bind | 9.20.21-160000.1.1 |
| SUSE:Linux Enterprise Server for SAP applications 16.0 | bind | 9.20.21-160000.1.1 |
| Ubuntu:18.04:LTS | isc-dhcp | no fix |
| Ubuntu:20.04:LTS | bind9-libs | no fix |
| Ubuntu:22.04:LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.3 |
| Ubuntu:22.04:LTS | bind9-libs | no fix |
| Ubuntu:24.04:LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.3 |
| Ubuntu:24.04:LTS | isc-dhcp | no fix |
| Ubuntu:25.10 | bind9 | 1:9.20.11-1ubuntu2.2 |
| Ubuntu:25.10 | isc-dhcp | no fix |
| Ubuntu:26.04:LTS | isc-dhcp | no fix |
| openSUSE:Leap 16.0 | bind | 9.20.21-160000.1.1 |
| openSUSE:Tumbleweed | bind | 9.20.21-1.1 |