CVE catalog
CVE-2026-5947
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. I
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 1.39% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | bind9 | sid | 1:9.20.30-1 | fixed |
| Debian | bind9 | forky | 1:9.20.30-1 | fixed |
| Debian | bind9 | trixie | 1:9.20.26-1~deb13u1 | fixed |
| Debian | bind9 | trixie-security | 1:9.20.30-1~deb13u1 | fixed |
| Debian | bind9 | bookworm | 1:9.18.49-1~deb12u1 | not affected |
| Debian | bind9 | bookworm-security | 1:9.18.49-1~deb12u3 | not affected |
| Cpe | bind9 | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9-dev | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9-dnsutils | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9-doc | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9-host | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9-libs | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9-utils | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind9utils | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | dnsutils | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | fixed |
| Cpe | bind | Not reported | 9.20.23 | fixed |
| Cpe | bind | Not reported | 9.21.22 | fixed |
| Cpe | bind | Not reported | 9.21.22 | fixed |
| Alpine | bind | 3.20 | 9.18.49-r0 | fixed |
| Alpine | bind | 3.21 | 9.18.49-r0 | fixed |
| Alpine | bind | 3.22 | 9.20.23-r0 | fixed |
| Alpine | bind | 3.23 | 9.20.23-r0 | fixed |
| Alpine | bind | 3.24 | 9.20.23-r0 | fixed |
| Ubuntu | bind9 | 25.10 | 1:9.20.4-3ubuntu1 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.4-3ubuntu2 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.4-3ubuntu3 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.9-2ubuntu1 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.10-1ubuntu1 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.11-1ubuntu1 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.11-1ubuntu2 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.11-1ubuntu2.1 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.11-1ubuntu2.2 | vulnerable |
| Ubuntu | bind9 | 25.10 | 1:9.20.11-1ubuntu2.4 | fixed |
| Ubuntu | bind9 | 26.04 | 1:9.20.11-1ubuntu2 | vulnerable |
| Ubuntu | bind9 | 26.04 | 1:9.20.11-1ubuntu3 | vulnerable |
| Ubuntu | bind9 | 26.04 | 1:9.20.18-1ubuntu1 | vulnerable |
| Ubuntu | bind9 | 26.04 | 1:9.20.18-1ubuntu2 | vulnerable |
| Ubuntu | bind9 | 26.04 | 1:9.20.18-1ubuntu2.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | bind9 | source | sid | 1:9.20.23-1 | not yet assigned | Not reported | Not reported |
| Debian | bind9 | source | forky | 1:9.20.23-1 | not yet assigned | Not reported | Not reported |
| Debian | bind9 | source | trixie | 1:9.20.23-1~deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | bind9 | source | bookworm | Not affected | unimportant | Not reported | Not reported |
| Cpe | bind9 | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9-dev | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9-dnsutils | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9-doc | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9-host | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9-libs | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9-utils | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind9utils | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | dnsutils | cpe | Not reported | 1:9.18.39-0ubuntu0.24.04.5 | Not reported | Not reported | Not reported |
| Cpe | bind | cpe | Not reported | 9.20.23 | Not reported | Not reported | Not reported |
| Cpe | bind | cpe | Not reported | 9.21.22 | Not reported | Not reported | Not reported |
| Cpe | bind | cpe | Not reported | 9.21.22 | Not reported | NVD-CVE-2026-5947 | Not reported |
| Alpine | bind | apk | 3.20 | 9.18.49-r0 | Not reported | ALPINE-CVE-2026-5947 | Not reported |
| Alpine | bind | apk | 3.21 | 9.18.49-r0 | Not reported | ALPINE-CVE-2026-5947 | Not reported |
| Alpine | bind | apk | 3.22 | 9.20.23-r0 | Not reported | ALPINE-CVE-2026-5947 | Not reported |
| Alpine | bind | apk | 3.23 | 9.20.23-r0 | Not reported | ALPINE-CVE-2026-5947 | Not reported |
| Alpine | bind | apk | 3.24 | 9.20.23-r0 | Not reported | ALPINE-CVE-2026-5947 | Not reported |
| Ubuntu | bind9 | deb | 25.10 | 1:9.20.11-1ubuntu2.4 | Not reported | UBUNTU-CVE-2026-5947 | Not reported |
| Ubuntu | bind9 | deb | 26.04 | 1:9.20.18-1ubuntu2.1 | Not reported | UBUNTU-CVE-2026-5947 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [bind9]Not affected
Details (6)
1:9.18.49-1~deb12u1· amd64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· arm64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· amd64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· arm64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· amd64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· arm64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9-dev]Not affected
Source package: [bind9]
Details (6)
1:9.18.49-1~deb12u1· amd64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· arm64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· amd64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· arm64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· amd64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· arm64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9-dnsutils]Not affected
Source package: [bind9]
Details (6)
1:9.18.49-1~deb12u1· amd64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· arm64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· amd64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· arm64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· amd64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· arm64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9-doc]Not affected
Source package: [bind9]
Details (6)
1:9.18.49-1~deb12u1· all · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· all · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· all · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· all · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· all · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· all · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9-host]Not affected
Source package: [bind9]
Details (6)
1:9.18.49-1~deb12u1· amd64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· arm64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· amd64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· arm64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· amd64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· arm64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9-libs]Not affected
Source package: [bind9]
Details (6)
1:9.18.49-1~deb12u1· amd64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· arm64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· amd64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· arm64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· amd64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· arm64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9-utils]Not affected
Source package: [bind9]
Details (6)
1:9.18.49-1~deb12u1· amd64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· arm64 · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· amd64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.20.23-1~deb13u1~bpo12+1· arm64 · bookworm-backportsNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· amd64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· arm64 · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [bind9utils]Not affected
Source package: [bind9]
Details (4)
1:9.18.49-1~deb12u1· all · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· all · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· all · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· all · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
- [dnsutils]Not affected
Source package: [bind9]
Details (4)
1:9.18.49-1~deb12u1· all · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u1· all · bookwormNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· all · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
1:9.18.49-1~deb12u2· all · bookworm-securityNot affected
nvd · bind9 · debian · bookworm
[Debian 13 (Trixie)]
- [bind9]Fixed
Details (6)
1:9.20.23-1~deb13u1· amd64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· arm64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· arm64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
- [bind9-dev]Fixed
Source package: [bind9]
Details (6)
1:9.20.23-1~deb13u1· amd64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· arm64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· arm64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
- [bind9-dnsutils]Fixed
Source package: [bind9]
Details (6)
1:9.20.23-1~deb13u1· amd64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· arm64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· arm64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
- [bind9-doc]Fixed
Source package: [bind9]
Details (6)
1:9.20.23-1~deb13u1· all · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· all · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· all · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· all · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· all · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· all · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
- [bind9-host]Fixed
Source package: [bind9]
Details (6)
1:9.20.23-1~deb13u1· amd64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· arm64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· arm64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
- [bind9-libs]Fixed
Source package: [bind9]
Details (6)
1:9.20.23-1~deb13u1· amd64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· arm64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· arm64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
- [bind9-utils]Fixed
Source package: [bind9]
Details (6)
1:9.20.23-1~deb13u1· amd64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.23-1~deb13u1· arm64 · trixieFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.26-1~deb13u1· arm64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.29-1~deb13u1· amd64 · trixie-security · Historical versionFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
1:9.20.30-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
1:9.20.23-1~deb13u1nvd · bind9 · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-5947]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-5947]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-5947]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-5947]
- [https://security-tracker.debian.org/tracker/CVE-2026-5947]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5947.json]
- [https://ubuntu.com/security/notices/USN-8293-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-1626.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]