Vulnerability in Isc (CVE-2026-5946)
Summary
Vulnerability in Isc (CVE-2026-5946). Risk of unauthorized operations or information disclosure. Exploitable via named.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-5946 has been found in Isc.
Attackers can target a specific entry point like named over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Isc CVE-2026-5946" on the vendor's site.
CVE-2026-5946 (Isc) — CWE-20 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: named / CHAOS / HESIOD / ANY
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in Isc. Attackers reach the vulnerable code path via named without authentication.
Check the vendor advisory for the affected versions of Isc. Attack surface: named / CHAOS / HESIOD / ANY.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Isc' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Isc' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Iscを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Alpine Linux ALPINE-CVE-2026-5946 bind Fixed in: 9.18.49-r0
- BellSoft Alpaquita BELL-CVE-2026-5946 bind Fixed in: 9.20.23-r0
- Debian DEBIAN-CVE-2026-5946 bind9
- Ubuntu UBUNTU-CVE-2026-5946 bind9
References
- advisory kb.isc.org
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory access.redhat.com
- patch downloads.isc.org
- patch downloads.isc.org
- patch downloads.isc.org
- report bugzilla.redhat.com
- web nvd.nist.gov
- web github.com
- web access.redhat.com
- web security.access.redhat.com