F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-09-22
• Critical severity: CVSS 9.8

[ Description ]Official description

When a BIG-IP APM access policy and an OAuth profile are configured on a virtual server, specific malicious traffic can lead to remote code execution (RCE). This vulnerability is only present when BIG-IP APM is configured as an OAuth Authorization Server. Deployments using APM strictly as an OAuth Client / Resource Server (without OAuth authorization server profiles configured) are not affected by this vulnerability. Impact: This vulnerability allows an unauthenticated attacker to perform remote code execution. The BIG-IP system in Appliance mode is also vulnerable. This is a data plane issue; there is no control plane exposure. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CISA: 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.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 25 Sep 2026): 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.

• Security bulletin: F5 K000162605Vendor patch or bulletin · CERT-FR · my.f5.com/manage/s/article/K000162605, cited by CERT-FR CERTFR-2026-AVI-1220

[ Advisories ]Government CERT advisories

• CERT-FR23 Sep 2026CERTFR-2026-AVI-1220

  Vulnerability in F5 BIG-IP Translated from French

  A vulnerability has been discovered in F5 BIG-IP. It allows an attacker to cause remote arbitrary code execution. The vendor reports that vulnerability CVE-2026-94127 is being actively exploited. Indicators of…

  CVE-2026-94127

[ References ]References

• my.f5.com/manage/s/article/K000162605Vendor Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource