Law Firms Escalate Investor Actions Over F5 Breach Disclosures as Lead‑Plaintiff Deadline Nears

Law firms are courting shareholders after F5 disclosed a nation‑state breach that exposed portions of its BIG‑IP source code.

Overview

Portnoy Law Firm said it has opened an investigation into possible securities fraud at F5 and may file a class action on behalf of investors.
Robbins LLP reminded shareholders that a class action is on file for those who bought F5 securities between October 28, 2024 and October 27, 2025, with a lead‑plaintiff deadline of February 17, 2026.
The Schall Law Firm invited investors to seek lead‑plaintiff status, alleging F5 made false or misleading statements about its security posture and growth prospects.
F5’s October 15, 2025 disclosure reported long‑term, persistent access by a highly sophisticated nation‑state actor and exfiltration of files including portions of BIG‑IP source code and information on undisclosed vulnerabilities.
F5 shares fell roughly 10–14% following the October 15 disclosure and declined about 11% after the October 27 results and reduced fiscal‑2026 outlook that the company tied in significant part to breach impacts.