F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability

What it is

F5 BIG-IP APM contains a heap-based buffer overflow vulnerability when access policy and an OAuth profile are configured on a virtual server. This vulnerability could allow an unauthenticated attacker to perform remote code execution.

Who's affected

Anyone using F5 BIG-IP APM.

Under attack?

Yes. CISA added this to its catalog of actively exploited vulnerabilities on Sep 22, 2026.

What to do

Install the vendor's security update. If there isn't one yet, apply the vendor's workaround, or stop using the product until it's fixed. CISA lists this as actively exploited, so treat it as urgent.

Fixed in

See the vendor's advisory

CISA deadline

Federal agencies must fix this by Sep 25, 2026. Everyone else should treat that as a ceiling, not a target.

CISA's instruction

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.