CVE-2026-94127: F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability

Patch now

CRITICAL 9.8EXPLOITEDREMOTEUPGRADE

CVE-2026-94127 is a critical-severity flaw (CVSS 9.8) affecting big-ip access policy manager, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 a

Why this priority

Critical severity
Exploited in the wild (CISA KEV)
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.2% (top 17%)
CISA exploited list	Yes, fix due 2026-09-25
Weakness	CWE-122
Published	2026-09-22
Last modified	2026-09-23

Publisher (CNA): F5 Networks · Vendor: f5

Am I affected?

Timeline

2026-09-22Exploited Added to the CISA Known Exploited Vulnerabilities list
2026-09-22 15:17 UTCPublished CVE record published
2026-09-23 14:32 UTCUpdated Record last modified
2026-09-25Deadline CISA due date for US federal agencies to patch

f5 big-ip access policy manager UPGRADE

Affected: >= 17.0.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1 · 21.1.0

Fixed in: newer than 17.5.1

Safe to downgrade to: a release before 17.0.0

1. Check installed version

apt-cache policy big-ip-access-policy-manager || rpm -q big-ip-access-policy-manager || big-ip-access-policy-manager --version

2. UPGRADE to newer than 17.5.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade big-ip-access-policy-manager

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade big-ip-access-policy-manager

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 17.0.0 (Debian / Ubuntu)

apt-cache madison big-ip-access-policy-manager sudo apt install big-ip-access-policy-manager=<VERSION_BEFORE_17.0.0> sudo apt-mark hold big-ip-access-policy-manager

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list big-ip-access-policy-manager sudo dnf downgrade big-ip-access-policy-manager-<VERSION_BEFORE_17.0.0> sudo dnf versionlock add big-ip-access-policy-manager

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Fedora 46 · retext · FIXED · 8.1.0-1.fc46 · FEDORA-2026-0602a84203 · source

sudo dnf upgrade --advisory=FEDORA-2026-0602a84203

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: watchtowrlabs/watchTowr-vs-f5-bigip-PreAuth-RCE-CVE-2026-94127 (15 stars)
GitHub PoC: FurkanKAYAPINAR/CVE-2026-94127 (0 stars)

Advisories and coverage

Research and news

watchTowr Labs: Is This A Joke? In The Auth Header? (F5 BIG-IP UnAuth Heap-Overflow to RCE CVE-2026-94127) 2026-09-23

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

References

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