Serious F5 Breach

Schneier •Bruce Schneier • October 23, 2025

This is bad: F5, a Seattle-based maker of networking software, disclosed the breach on Wednesday. F5 said a “sophisticated” threat group working for an undisclosed nation-state government had surreptitiously and persistently dwelled in its network over a “long-term.” Security researchers who have responded to similar intrusions in the past took the language to mean the hackers were inside the F5 network for years . During that time, F5 said, the hackers took control of the network segment the company uses to create and distribute updates for BIG IP, a line of server appliances that F5 ...

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

F5 Breach Exposes Networks to State-Linked Attacks F5 disclosed a significant cybersecurity breach on November 5, 2025, involving a sophisticated threat group linked to a nation-state. The attackers reportedly gained long-term access to F5's network, potentially compromising operational technology systems. Security experts warn that the stolen data could facilitate further state-sponsored attacks. 2 sources 19

Extracted Entities

Attack Types (1)

Data Breach

Serious F5 Breach

The full story

Extracted Entities

Attack Types (1)

Companies (1)