PatchTheCVECVE-2026-42409: When an HTTP/2 profile and an iRule containing the HTTP::redirect or HTTP::respond command are configured on a
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This month
HIGH 7.5REMOTEWATCHLISTUPGRADEUPGRADEUPGRADE
CVE-2026-42409 is a high-severity flaw (CVSS 7.5) affecting big-ip next cloud-native network functions, big-ip next for kubernetes, big-ip access policy manager. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
When an HTTP/2 profile and an iRule containing the HTTP::redirect or HTTP::respond command are configured on a virtual server, undisclosed requests can cause 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
- On your watchlist
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-476 |
| 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
- Published CVE record published
- Updated Record last modified
f5 big-ip next cloud-native network functions UPGRADE
Affected: >= 1.1.0 and <= 1.4.0 · >= 2.0.0 and <= 2.0.2
Fixed in: newer than 2.0.2
Safe to downgrade to: a release before 1.1.0
1. Check installed version
apt-cache policy big-ip-next-cloud-native-network-functions || rpm -q big-ip-next-cloud-native-network-functions || big-ip-next-cloud-native-network-functions --version
2. UPGRADE to newer than 2.0.2 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade big-ip-next-cloud-native-network-functions
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade big-ip-next-cloud-native-network-functions
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 1.1.0 (Debian / Ubuntu)
apt-cache madison big-ip-next-cloud-native-network-functions
sudo apt install big-ip-next-cloud-native-network-functions=<VERSION_BEFORE_1.1.0>
sudo apt-mark hold big-ip-next-cloud-native-network-functions
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list big-ip-next-cloud-native-network-functions
sudo dnf downgrade big-ip-next-cloud-native-network-functions-<VERSION_BEFORE_1.1.0>
sudo dnf versionlock add big-ip-next-cloud-native-network-functions
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 next for kubernetes UPGRADE
Affected: >= 2.0.0 and <= 2.1.0
Fixed in: newer than 2.1.0
Safe to downgrade to: a release before 2.0.0
1. Check installed version
apt-cache policy big-ip-next-for-kubernetes || rpm -q big-ip-next-for-kubernetes || big-ip-next-for-kubernetes --version
2. UPGRADE to newer than 2.1.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade big-ip-next-for-kubernetes
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade big-ip-next-for-kubernetes
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 2.0.0 (Debian / Ubuntu)
apt-cache madison big-ip-next-for-kubernetes
sudo apt install big-ip-next-for-kubernetes=<VERSION_BEFORE_2.0.0>
sudo apt-mark hold big-ip-next-for-kubernetes
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list big-ip-next-for-kubernetes
sudo dnf downgrade big-ip-next-for-kubernetes-<VERSION_BEFORE_2.0.0>
sudo dnf versionlock add big-ip-next-for-kubernetes
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 access policy manager UPGRADE
Affected: 21.0.0 · >= 16.1.0 and <= 16.1.6 · >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1
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-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 16.1.0 (Debian / Ubuntu)
apt-cache madison big-ip-access-policy-manager
sudo apt install big-ip-access-policy-manager=<VERSION_BEFORE_16.1.0>
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_16.1.0>
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.
f5 big-ip advanced firewall manager UPGRADE
Affected: 21.0.0 · >= 16.1.0 and <= 16.1.6 · >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1
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-firewall-manager || rpm -q big-ip-advanced-firewall-manager || big-ip-advanced-firewall-manager --version
2. UPGRADE to newer than 17.5.1 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade big-ip-advanced-firewall-manager
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade big-ip-advanced-firewall-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-advanced-firewall-manager
sudo apt install big-ip-advanced-firewall-manager=<VERSION_BEFORE_16.1.0>
sudo apt-mark hold big-ip-advanced-firewall-manager
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list big-ip-advanced-firewall-manager
sudo dnf downgrade big-ip-advanced-firewall-manager-<VERSION_BEFORE_16.1.0>
sudo dnf versionlock add big-ip-advanced-firewall-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 advanced web application firewall UPGRADE
Affected: 21.0.0 · >= 16.1.0 and <= 16.1.6 · >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1
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 analytics UPGRADE
Affected: 21.0.0 · >= 16.1.0 and <= 16.1.6 · >= 17.1.0 and <= 17.1.3 · >= 17.5.0 and <= 17.5.1
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-analytics || rpm -q big-ip-analytics || big-ip-analytics --version
2. UPGRADE to newer than 17.5.1 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade big-ip-analytics
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade big-ip-analytics
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-analytics
sudo apt install big-ip-analytics=<VERSION_BEFORE_16.1.0>
sudo apt-mark hold big-ip-analytics
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list big-ip-analytics
sudo dnf downgrade big-ip-analytics-<VERSION_BEFORE_16.1.0>
sudo dnf versionlock add big-ip-analytics
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.
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-2026-42409?
big-ip next cloud-native network functions: upgrade to newer than 2.0.2; big-ip next for kubernetes: upgrade to newer than 2.1.0; big-ip access policy manager: upgrade to newer than 17.5.1. Exact commands for each OS are on this page.
Is CVE-2026-42409 being exploited?
CVE-2026-42409 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-2026-42409 affect?
CVE-2026-42409 affects big-ip next cloud-native network functions, big-ip next for kubernetes, big-ip access policy manager. Severity is high (CVSS 7.5). When an HTTP/2 profile and an iRule containing the HTTP::redirect or HTTP::respond command are configured on a virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) process to terminate. Note: Software ver
How urgent is CVE-2026-42409?
Priority 41/100. High severity; Remotely exploitable, no login, no user action; On your watchlist
Software pages
Kubernetes vulnerabilities · F5 BIG-IP vulnerabilities