Item 1.05 section not located in normalized markdown

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of Earliest Event Reported):

October 15, 2025

F5, Inc.

(Exact name of registrant as specified in its charter)

| Washington | 000-26041 | 91-1714307 | ||||||||||||
| (State or other jurisdiction | (Commission | (IRS Employer | ||||||||||||
| of incorporation) | File Number) | Identification No.) |

| 801 5th Avenue | ||||||||||||||||||||
| Seattle | , | WA | 98104 | |||||||||||||||||
| (Address of principal executive offices) | (Zip Code) |

Registrant’s telephone number, including area code (206) 272-5555

Not Applicable

Former name or former address, if changed since last report

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

| Title of each class | Trading Symbol(s) | Name of each exchange on which registered | ||||||
| Common stock, no par value | FFIV | NASDAQ Global Select Market |

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

| Item 1.05 | Material Cybersecurity Incidents |

On August 9, 2025, F5, Inc. (the “Company”, “F5”, “we”, or “our”) learned that a highly sophisticated nation-state threat actor had gained unauthorized access to certain Company systems. The Company promptly activated its incident response processes, and has taken extensive actions to contain the threat actor. To support these activities, the Company engaged leading external cybersecurity experts.

The Company believes its containment actions have been successful and, since the initiation of its containment efforts, has not observed any evidence of new unauthorized activity. The investigation, monitoring, and related activities are ongoing. The Company is actively engaged with federal law enforcement and government partners in connection with this incident. Additionally, the Company is implementing further measures to strengthen its security environment and protect its customers.

During the course of its investigation, the Company determined that the threat actor maintained long-term, persistent access to certain F5 systems, including the BIG-IP product development environment and engineering knowledge management platform. Through this access, certain files were exfiltrated, some of which contained certain portions of the Company’s BIG-IP source code and information about undisclosed vulnerabilities that it was working on in BIG-IP. We are not aware of any undisclosed critical or remote code vulnerabilities, and we are not aware of active exploitation of any undisclosed F5 vulnerabilities. We have no evidence of modification to our software supply chain, including our source code and our build and release pipelines. This assessment has been validated through independent reviews by leading cybersecurity research firms.

We have no evidence of access to, or exfiltration of, data from our CRM, financial, support case managem