Actively exploited · Published Sep 22, 2026 · Assigned by f5

CVE-2026-94127BIG-IP APM OAuth vulnerability

Critical 9.8 Exploited

In plain English

A critical-severity heap buffer overflow in BIG-IP from F5. Attackers are actively exploiting it in the wild (listed by CISA on September 22, 2026). The chance it is exploited in the next 30 days is estimated at 26.6% (higher than 98% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. 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.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)26.6%top 2.0% of all CVEs
Exploited in the wildYesCISA KEV since Sep 22, 2026
Attack tooling1Public PoC

CISA guidance

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.

Federal agencies must remediate by Sep 25, 2026.

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.

Affected products (as reported)

VendorProductVersions
F5 BIG-IP 21.1.0 – before Hotfix-BIGIP-21.1.0.2.0.30.22-ENG17.5.0 – before Hotfix-BIGIP-17.5.1.9.0.160.12-ENG17.1.0 – before Hotfix-BIGIP-17.1.3.5.0.41.14-ENG

Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References