Cyber Brief: F5 Post-Breach & CISA Exploited Vulnerabilities

The cybersecurity landscape remains fluid, with new advisories highlighting vendor vulnerabilities and targeted exploits. Today’s stories underline the ongoing need for proactive patching and supplier vigilance across UK businesses.

CISA and NCSC issue coordinated warnings on F5 post-breach vulnerabilities

Following confirmation of a state-backed breach into F5 Networks’ development environment, both the Cybersecurity and Infrastructure Security Agency (CISA) and the UK’s National Cyber Security Centre (NCSC) have reiterated urgent guidance for all organisations using F5 BIG-IP, BIG-IQ, and NGINX products. The advisories highlight increased scanning activity targeting F5 devices globally. Security teams are instructed to review configurations, remove internet-facing management interfaces, and apply the latest patches released this week.

Why it matters: Many UK enterprises and public-sector suppliers depend on F5 infrastructure to manage network traffic and application security. A compromise at the vendor level means attackers could weaponise known flaws more quickly than before. Treat this as a live exposure event — patch immediately, validate network segmentation, and monitor for abnormal login attempts.
Source: NCSC / CISA

CISA adds new vulnerabilities to its Known Exploited Vulnerabilities (KEV) list

The latest update to CISA’s KEV catalogue names multiple vulnerabilities actively exploited in the wild — including a Microsoft Windows SMB client flaw and a Kentico Xperience CMS bug. Vendors have already released fixes, but reports suggest many affected organisations have yet to implement them. The agency stresses that these are high-risk weaknesses requiring immediate attention across both government and commercial sectors.

Why it matters: A place on the KEV list signals active exploitation. For UK SMEs, this provides a practical prioritisation tool — patch the systems in that catalogue first. Delayed remediation allows attackers to leverage already-published exploit code, turning routine vulnerabilities into business-stopping incidents.
Source: CISA

🔍 Today’s Key Actions

1. Inventory and patch F5 devices immediately; restrict management access to internal networks only.
2. Cross-check infrastructure against CISA’s KEV catalogue and verify all patches are applied.
3. Review supplier dependencies — ensure vendors handling your infrastructure are also compliant with current advisories.
4. Increase monitoring for anomalies — particularly remote logins, unusual web-application traffic, or device-configuration changes.
5. Brief leadership teams with clear evidence of remediation steps to reinforce board-level confidence in resilience.

💬 Secarma Insight

Today’s alerts underline how interconnected modern cybersecurity has become. A vendor compromise can ripple through entire supply chains within hours, and exploited vulnerabilities rarely wait for convenient patch cycles. Secarma’s ACT Framework — Advise, Certify, Test — helps organisations turn fast-moving advisories into structured resilience.
Get in touch with us to bridge the gap between threat intelligence and measurable resilience.