🛡️ CVE-2026-5946 on Debian — bind9

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Multiple flaws have been identified in named related to the handling of DNS messages whose CLASS is not Internet (IN) — for example, CHAOS or HESIOD, or DNS messages that specify meta-classes (ANY or NONE) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (UPDATE), zone change notifications (NOTIFY), or processing of IN-specific record types in non-IN data — can cause assertion failures in named. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

Distribution advisory

This page covers CVE-2026-5946 as tracked by Debian, for the package bind9. The fix is available in version 1:9.20.23-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

DEBIAN-CVE-2026-5946 is classified as CWE-20: Improper Input Validation. The application accepts input without checking that it has the expected form, so malformed values reach code that assumes they are well formed.

Affected software

DEBIAN-CVE-2026-5946 is recorded against 1 package.

  • bind9 (fixed in 1:9.20.23-1)

Timeline and source

Published on 20 May 2026 and last revised on 18 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2026-5946 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-05-20
Updated 2026-08-20
Modified 2026-08-18
Fix URL N/A

Affected Packages

Software From version Fixed in
bind9 — 1:9.20.23-1

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