CVEs / CVE-2026-94127
CVE-2026-94127: F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability
- Known exploited in the CISA KEV catalog since 22 Sep 2026
- critical 9.3 CVSS 4.0 (from the CNA)
- EPSS 24.9% chance of exploitation in the next 30 days, higher than 97% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2026-94127
Summary
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.
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 and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| F5 BIG-IP | from 21.1.0, before Hotfix-BIGIP-21.1.0.2.0.30.22-ENG | Hotfix-BIGIP-21.1.0.2.0.30.22-ENG |
| F5 BIG-IP | from 17.5.0, before Hotfix-BIGIP-17.5.1.9.0.160.12-ENG | Hotfix-BIGIP-17.5.1.9.0.160.12-ENG |
| F5 BIG-IP | from 17.1.0, before Hotfix-BIGIP-17.1.3.5.0.41.14-ENG | Hotfix-BIGIP-17.1.3.5.0.41.14-ENG |
Exploitation
| In CISA KEV since | 22 Sep 2026 |
|---|---|
| Due date for US federal agencies | 25 Sep 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 4.0 | 9.3 criticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-122 |
References
- CVE-2026-94127 on NVD
- CVE-2026-94127 in the CISA KEV catalog
- https://my.f5.com/manage/s/article/K000162605 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://my.f5.com/manage/s/article/K000162605 Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-94127 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.