What is CVE-2026-94127?

CVE-2026-94127 is a critical-severity vulnerability in F5 Big-Ip, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-09-22.

How severe is CVE-2026-94127?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2026-94127 known to be exploited?

Yes. CVE-2026-94127 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-22), indicating it is being actively exploited.

Buffer overflow in F5 Big-Ip

CVE-2026-94127

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.

Vulnerability class: Buffer Overflow

Published 2026-09-22 · last modified 2026-09-23.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

F5 Big-Ip

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-09-22. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-09-25.

Required action: 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.

References

my.f5.com/manage/s/article/K000162605 (vendor-advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0

Frequently asked questions

What is CVE-2026-94127?: CVE-2026-94127 is a critical-severity vulnerability in F5 Big-Ip, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-09-22.
How severe is CVE-2026-94127?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-94127 known to be exploited?: Yes. CVE-2026-94127 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-22), indicating it is being actively exploited.