# F5 breached by nation-state actor: BIG-IP source code and undisclosed bugs stolen · pwn.watch

> F5 disclosed that a sophisticated nation-state actor had long-term access to its BIG-IP development and engineering systems and stole parts of the BIG-IP source code, information on undisclosed vulnerabilities and some customer configuration data. CISA issued Emergency Directive 26-01 ordering agencies to inventory and patch F5 gear. Researchers linked it to China-nexus UNC5221 and BRICKSTORM.

Page: https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025 · generated 2026-10-23T03:54:42.456Z

## Status
- Severity: critical · status: closed · patch: patched
- Product: F5 BIG-IP (vendor breach)
- Started: 2025-08-09 · closed: 2025-10-15
- Affected: BIG-IP, F5OS, BIG-IP Next and others (see F5 K000154696 and Oct 2025 Quarterly Security Notification)
- Fixed in: F5 October 2025 Quarterly Security Notification releases

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025/feed.xml
- JSON Feed: https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025.json
- This file: https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025/llms.txt

## Updates (newest first)
- 2025-10-15: F5 discloses the breach (SEC 8-K) and ships patches (https://my.f5.com/manage/s/article/K000154696)
- 2025-10-15: CISA issues Emergency Directive 26-01 for F5 devices (https://www.cisa.gov/news-events/directives/ed-26-01-mitigate-vulnerabilities-f5-devices)
- 2025-08-09: F5 learns of the intrusion (https://www.sec.gov/Archives/edgar/data/1048695/000104869525000149/ffiv-20251015.htm)

## Fix brief
# Security brief: F5 breached by nation-state actor: BIG-IP source code and undisclosed bugs stolen

Source: https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025 · status: closed (closed Oct 15, 2025) · severity: critical · updated Oct 15, 2025

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
F5 disclosed that a sophisticated nation-state actor had long-term access to its BIG-IP development and engineering systems and stole parts of the BIG-IP source code, information on undisclosed vulnerabilities and some customer configuration data. CISA issued Emergency Directive 26-01 ordering agencies to inventory and patch F5 gear. Researchers linked it to China-nexus UNC5221 and BRICKSTORM.

Severity detail: Nation-state theft of source code and undisclosed vulnerability info; CISA Emergency Directive

- Product: F5 BIG-IP (vendor breach)

## Affected versions
- BIG-IP, F5OS, BIG-IP Next and others (see F5 K000154696 and Oct 2025 Quarterly Security Notification)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- F5 October 2025 Quarterly Security Notification releases

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Oct 15, 2025: F5 discloses the breach (SEC 8-K) and ships patches
- Oct 15, 2025: CISA issues Emergency Directive 26-01 for F5 devices
- Aug 9, 2025: F5 learns of the intrusion

## Advisories
- [F5 Security Incident (K000154696)](https://my.f5.com/manage/s/article/K000154696) (F5)
- [F5 Form 8-K (2025-10-15)](https://www.sec.gov/Archives/edgar/data/1048695/000104869525000149/ffiv-20251015.htm) (SEC)
- [ED 26-01: Mitigate Vulnerabilities in F5 Devices](https://www.cisa.gov/news-events/directives/ed-26-01-mitigate-vulnerabilities-f5-devices) (CISA)

## Write-ups & news
- [F5 BIG-IP Breach: UNC5221, BRICKSTORM & CISA Directive](https://www.zscaler.com/blogs/security-research/f5-security-incident-advisory)

## Caveats
Attribution to UNC5221/BRICKSTORM comes from third-party reporting; F5 itself said only 'nation-state'. The Aug 9 discovery date is from F5's disclosure.

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Machine-readable: https://pwn.watch/i/f5-nation-state-breach-big-ip-source-code-2025.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.