CVE-2026-94127 F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability
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.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 22 Sep 2026.
- Rated Critical severity (CVSS 9.8, scored by Vendor).
- This product type is often exposed to the internet, which is where attackers scan for it first.
- It has been in the catalogue for 45 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
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.
Affected Versions
| Product | Versions |
|---|---|
| F5 BIG-IP | 21.1.0 to before Hotfix-BIGIP-21.1.0.2.0.30.22-ENG 17.5.0 to before Hotfix-BIGIP-17.5.1.9.0.160.12-ENG 17.1.0 to before Hotfix-BIGIP-17.1.3.5.0.41.14-ENG |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for F5 BIG-IP APM. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
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.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
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