F5 BIG-IP: denial-of-service vulnerability | 09/21
HKCERT lists security issues in F5 BIG-IP, with potential impacts including service disruption.
Basis: the official source labels this high risk. GDMME follow-up priority uses official ratings and headline/summary rules. It is not a CVSS score or official vulnerability rating, and does not confirm that your business is affected.
Source severity
高度風險（HKCERT）
Affected scope
Scope listed in the advisory: BIG-IP (DNS); 17.1.0 - 17.1.3; 17.5.0 - 17.5.1; 21.1.0.
Official recommendations
Automatically extracted recommendation passages from the official source, retained in the source language. Check the complete advisory.
- 處理方法：
- 透過以下方法以緩解此漏洞的影響：
- 在 validating resolver DNS cache 中停用 DNSSEC
- 切換至 Resolver 或 Transparent cache 類型
- 在 DNS profile 中停用 Use BIND Server on BIG-IP 選項
- 請瀏覽供應商之網站 以獲得更多詳細資料
- 安裝供應商提供的臨時處理方法：
- https://my.f5.com/manage/s/article/K000163335
The last successful extraction is used here. Check the official source for the latest content.
Source text collected (Hong Kong time)：2026/10/12 02:44 HKT
官方原文建議自動摘錄 未作逐篇人工分析或翻譯；請核對完整公告、現行版本及適用性
GDMME recommended actions
GDMME recommendations · automatically organised from explicit products and source signals, without individual human analysis. Confirm applicability against vendor guidance and your environment.
- Locate F5 deployments, running versions and service owners in your inventory or management console; compare them with the vendor applicability criteria. A named product does not mean every deployment is affected.
- Check internet-reachable management interfaces, VPN access and administrator accounts on F5. Restrict unnecessary exposure using vendor guidance after confirming administration and remote-work needs.
- Once F5 applicability is confirmed, check the official excerpt and complete vendor patch/mitigation instructions. Record before/after versions, test results and rollback steps; do not install updates solely from a news headline.
- Review administrator sign-ins, configuration changes and VPN sessions on F5 against authorised changes. Preserve logs and use the incident procedure for unfamiliar admin accounts or unauthorised changes.
Automatically organised (Hong Kong time)：2026/10/12 03:05 HKT
Educational information only. Confirm affected versions, mitigations and exploitation status with the original vendor advisory. Reports do not imply that GDMME equipment blocks every vulnerability.