CVE-2026-5947
Fixed in a distro release EPSS 1%CVSS 7.5
Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.
Products: ISC BIND 9, Red Hat Hardened Images, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine 3.20 | bind | 9.18.49-r0 |
| Alpine 3.21 | bind | 9.18.49-r0 |
| Alpine 3.22 | bind | 9.20.23-r0 |
| Alpine 3.23 | bind | 9.20.23-r0 |
| Alpine 3.24 | bind | 9.20.23-r0 |
| Debian 13 | bind9 | 1:9.20.23-1~deb13u1 |
| Debian 14 | bind9 | 1:9.20.23-1 |
| Red Hat hummingbird 1 | bind | 0:9.18.48-1.1.hum1 |
| Red Hat hummingbird 1 | bind-chroot | 0:9.18.48-1.1.hum1 |
| Red Hat hummingbird 1 | bind-devel | 0:9.18.48-1.1.hum1 |
| Red Hat hummingbird 1 | bind-dnssec-utils | 0:9.18.48-1.1.hum1 |
| Red Hat hummingbird 1 | bind-doc | 0:9.18.48-1.1.hum1 |
| Red Hat hummingbird 1 | bind-libs | 0:9.18.48-1.1.hum1 |
| Red Hat hummingbird 1 | bind-utils | 0:9.18.48-1.1.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 16.0 | bind | 9.20.23-160000.1.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | bind | 9.20.23-160000.1.1 |
| Ubuntu 22.04 LTS | bind9 | 1:9.18.39-0ubuntu0.22.04.4 |
| Ubuntu 24.04 LTS | bind9 | 1:9.18.39-0ubuntu0.24.04.5 |
| Ubuntu 25.10 | bind9 | 1:9.20.11-1ubuntu2.4 |
| Ubuntu 26.04 LTS | bind9 | 1:9.20.18-1ubuntu2.1 |
| openSUSE Leap 16.0 | bind | 9.20.23-160000.1.1 |
| openSUSE Tumbleweed | bind | 9.20.23-1.1 |