Vulnerability in bind9 (UBUNTU-CVE-2026-11605)

Summary

Vulnerability in bind9 (UBUNTU-CVE-2026-11605). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1:9.20.24-1ubuntu0.2 or later.

Original description

The description as published by the source.

The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time. This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.

Source: OSV.dev (Open Source Vulnerabilities) OSV

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 UBUNTU-CVE-2026-11605 has been found in bind9.
Risk of unauthorized operations or information disclosure.
What to do: upgrade bind9 to 1:9.20.24-1ubuntu0.2 or later.
If unsure, ask your IT team or search "bind9 UBUNTU-CVE-2026-11605" on the vendor's site.

UBUNTU-CVE-2026-11605 (bind9)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 1:9.20.24-1ubuntu0.2 — apply immediately
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.

❓ What is the problem

A vulnerability (unclassified) exists in bind9.

📍 Affected scope

Check the vendor advisory for the affected versions of bind9.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1:9.20.24-1ubuntu0.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'bind9' . 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

1
Identify exposure identify
```
grep -r 'bind9' . | 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 bind9 を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade bind9 to 1:9.20.24-1ubuntu0.2
```
ステージング環境で 1:9.20.24-1ubuntu0.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-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。

Affected packages

Ubuntu:26.04:LTS bind9

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:9.20.24-1ubuntu0.2"}]}]

References

advisory ubuntu.com
report ubuntu.com
report cve.org
report kb.isc.org