CVE-2026-41227: On an HTTP/2 virtual server with Layer 7 DoS Protection configured, undisclosed traffic can result in an incre

Routine

HIGH 7.5REMOTEUPGRADEUPGRADEUPGRADE

CVE-2026-41227 is a high-severity flaw (CVSS 7.5) affecting big-ip advanced web application firewall, big-ip application security manager, big-ip ddos hybrid defender. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

On an HTTP/2 virtual server with Layer 7 DoS Protection configured, undisclosed traffic can result in an increase in memory consumption causing the Traffic Management Microkernel (TMM) process to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-05-13
Last modified	2026-10-26

Publisher (CNA): F5 Networks · Vendor: f5

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-13 16:16 UTCPublished CVE record published
2026-10-26 17:10 UTCUpdated Record last modified

f5 big-ip advanced web application firewall UPGRADE

Affected: >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1 · >= 16.1.0 and <= 16.1.6

Fixed in: newer than 17.5.1

Safe to downgrade to: a release before 16.1.0

1. Check installed version

apt-cache policy big-ip-advanced-web-application-firewall || rpm -q big-ip-advanced-web-application-firewall || big-ip-advanced-web-application-firewall --version

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

sudo apt update && sudo apt install --only-upgrade big-ip-advanced-web-application-firewall

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade big-ip-advanced-web-application-firewall

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 16.1.0 (Debian / Ubuntu)

apt-cache madison big-ip-advanced-web-application-firewall sudo apt install big-ip-advanced-web-application-firewall=<VERSION_BEFORE_16.1.0> sudo apt-mark hold big-ip-advanced-web-application-firewall

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

dnf --showduplicates list big-ip-advanced-web-application-firewall sudo dnf downgrade big-ip-advanced-web-application-firewall-<VERSION_BEFORE_16.1.0> sudo dnf versionlock add big-ip-advanced-web-application-firewall

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.

f5 big-ip application security manager UPGRADE

Affected: >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1 · >= 16.1.0 and <= 16.1.6

Fixed in: newer than 17.5.1

Safe to downgrade to: a release before 16.1.0

1. Check installed version

apt-cache policy big-ip-application-security-manager || rpm -q big-ip-application-security-manager || big-ip-application-security-manager --version

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

sudo apt update && sudo apt install --only-upgrade big-ip-application-security-manager

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade big-ip-application-security-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 16.1.0 (Debian / Ubuntu)

apt-cache madison big-ip-application-security-manager sudo apt install big-ip-application-security-manager=<VERSION_BEFORE_16.1.0> sudo apt-mark hold big-ip-application-security-manager

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

dnf --showduplicates list big-ip-application-security-manager sudo dnf downgrade big-ip-application-security-manager-<VERSION_BEFORE_16.1.0> sudo dnf versionlock add big-ip-application-security-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.

f5 big-ip ddos hybrid defender UPGRADE

Affected: >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1 · >= 16.1.0 and <= 16.1.6

Fixed in: newer than 17.5.1

Safe to downgrade to: a release before 16.1.0

1. Check installed version

apt-cache policy big-ip-ddos-hybrid-defender || rpm -q big-ip-ddos-hybrid-defender || big-ip-ddos-hybrid-defender --version

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

sudo apt update && sudo apt install --only-upgrade big-ip-ddos-hybrid-defender

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade big-ip-ddos-hybrid-defender

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 16.1.0 (Debian / Ubuntu)

apt-cache madison big-ip-ddos-hybrid-defender sudo apt install big-ip-ddos-hybrid-defender=<VERSION_BEFORE_16.1.0> sudo apt-mark hold big-ip-ddos-hybrid-defender

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

dnf --showduplicates list big-ip-ddos-hybrid-defender sudo dnf downgrade big-ip-ddos-hybrid-defender-<VERSION_BEFORE_16.1.0> sudo dnf versionlock add big-ip-ddos-hybrid-defender

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.

Verify at the official source NVD · CVE Program · 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.

Quick answers

How do I fix CVE-2026-41227?

big-ip advanced web application firewall: upgrade to newer than 17.5.1; big-ip application security manager: upgrade to newer than 17.5.1; big-ip ddos hybrid defender: upgrade to newer than 17.5.1. Exact commands for each OS are on this page.

Is CVE-2026-41227 being exploited?

CVE-2026-41227 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-41227 affect?

CVE-2026-41227 affects big-ip advanced web application firewall, big-ip application security manager, big-ip ddos hybrid defender. Severity is high (CVSS 7.5). On an HTTP/2 virtual server with Layer 7 DoS Protection configured, undisclosed traffic can result in an increase in memory consumption causing the Traffic Management Microkernel (TMM) process to terminate. Note: Software versions which ha

How urgent is CVE-2026-41227?

Priority 36/100. High severity; Remotely exploitable, no login, no user action

Software pages

F5 BIG-IP vulnerabilities · Windows Defender vulnerabilities

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References

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