InfoSecBulletin Cybersecurity for mankind
F5 Networks has issued its Quarterly Security Notification, highlighting several vulnerabilities that may severely impact enterprise infrastructures. F5 rates these flaws as “Medium” severity, but the CVSS v4.0 framework scores the most critical issues at 8.2 (High), indicating serious risks for production environments using BIG-IP, NGINX, and similar components.
High-Risk Vulnerabilities Identified:
Citrix NetScaler SAML 0-Day Flaw Under Attack
Major Danish university breached, 200,000 users at risk
Microsoft’s X account hijacked to promote Clippy crypto scam
Critical cPanel, GitLab AI Gateway and Dell CSM Flaws Enable RCE And Admin Hijacking
Nearly 100,000 email addresses exposed in first AI-related data breach in Singapore
Hackers Exploit Zimbra Mail Servers: TeamViewer patched 5 critical flaws
Google Warns of Hackers Actively Exploiting Citrix 0-Day Flaws
CISA Warns Critical MikroTik RouterOS Flaw While Cisco SD-WAN Zero-Day Exploited in Attacks
Apple Zero-Day Exploited: Pentagon Data Breach Reportedly Exposes Sensitive Data of 3 Million People
JadePuffer Agentic AI targets and destroys Azure’s cloud resources
The advisory highlights three main vulnerabilities affecting BIG-IP Advanced WAF, NGINX Plus, and BIG-IP Container Ingress Services (CIS). Unpatched components can be prime targets for attackers since they manage important routing and load balancing for applications.
This vulnerability impacts BIG-IP Advanced Web Application Firewall (WAF) and Application Security Manager (ASM).
A score of 8.2 (High) means that remote attackers can bypass security filters or disrupt web application protections. This issue impacts versions 17.1.0 to 17.1.2, with a fix in version 17.1.3.
A significant flaw has been identified in the NGINX ecosystem, including NGINX Open Source, NGINX Plus, and the NGINX Ingress Controller.
| CVE ID | Component | Severity (CVSS v4.0) | Affected Versions |
|---|---|---|---|
| CVE-2026-22548 | BIG-IP Adv. WAF / ASM | 8.2 (High) | 17.1.0 – 17.1.2 |
| CVE-2026-1642 | NGINX Plus | 8.2 (High) | R32 – R36 P1 |
| CVE-2026-1642 | NGINX Open Source | 8.2 (High) | 1.3.0 – 1.29.4 |
| CVE-2026-1642 | NGINX Ingress Controller | 8.2 (High) | 5.3.0 – 5.3.2 |
| CVE-2026-22549 | BIG-IP Container Ingress | 6.9 (Medium) | 2.0.0 – 2.20.1 |
| CVE-2026-20730 | BIG-IP Edge Client (Win) | 2.0 (Low) | 7.2.5 – 7.2.6.1 |
| CVE-2026-20732 | BIG-IP Config Utility | 2.3 (Low) | 17.1.0 – 17.1.3 |
NGINX Gateway Fabric and Instance Manager also need individual patches based on deployment settings.
F5 revealed a configuration issue in BIG-IP SMTP modules (K000156643). Misconfigured email relay settings can lead to information leaks or unauthorized relaying, even if it’s not a software issue.
Administrators should apply the hardening measures introduced in versions 17.5.1.4 and 21.0.0.1.
Inventory Assets: Identify all in-scope BIG-IP and NGINX instances.
Verify Versions: Cross-check with the affected versions listed above.
Apply Patches: Implement urgently, especially for CVE-2026-22548 and CVE-2026-1642.
Harden Configurations: Review SMTP module settings to close configuration gaps.
Security teams should prioritize these updates to ensure the continued protection of application delivery pipelines and perimeter traffic management systems.
