CVE-2026-72254: netfilter: nft_fib: reject fib expression on the netdev egress hook
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nftfib: reject fib expression on the netdev egress hook
A fib expression in a netdev egress base chain dereferences nftin(pkt), NULL on the transmit path, causing a NULL pointer dereference at eval. nftfibvalidate() masks the hook with NFINET values, but netdev hook numbers are a separate enum that aliases them (NFNETDEVEGRESS == NFINETLOCALIN), so an egress chain passes validation and then faults.
Add nftfibnetdevvalidate() that limits each result/flag to the netdev hook where the device it reads exists: the input-device cases (OIF, OIFNAME, ADDRTYPE with FIIF) to ingress, the output-device case (ADDRTYPE with FOIF) to egress, ADDRTYPE with no device flag to both. Also restrict nftfibvalidate() to NFPROTOIPV4/IPV6/INET so its NFINET masks are not applied to another family's hooks.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-147.147 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1067.70 - Upgrade
Upgrade
ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - Upgrade
Upgrade
ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 6.8.0-1069.76 - Upgrade
Upgrade
ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - Upgrade
Upgrade
ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1066.74 - Upgrade
Upgrade
ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1052.56 - Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38~24.04.4 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1067.68 - Upgrade
Upgrade
ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-147.147.1 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1036.39 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1064.67 - Upgrade
Upgrade
ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1~24.04.1 - Upgrade
Upgrade
ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1033.38 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1062.63 - Upgrade
Upgrade
ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1067.70+fips1 - Upgrade
Upgrade
ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79+fips1 - Upgrade
Upgrade
ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-147.147+fips1 - Upgrade
Upgrade
ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79+fips1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-38.38 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1008.9 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.101-1 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 7.1.5-1 - Upgrade
Upgrade
debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.101-1~deb12u1 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.14-1 - Upgrade
Upgrade
debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
Upgrade
linux/Kernelto a version that resolves this vulnerability.Fixed in 6.1.191 - Upgrade
Upgrade
linux/Kernelto a version that resolves this vulnerability.Fixed in 6.6.148 - Upgrade
Upgrade
linux/Kernelto a version that resolves this vulnerability.Fixed in 6.12.101 - Upgrade
Upgrade
linux/Kernelto a version that resolves this vulnerability.Fixed in 6.18.42 - Upgrade
Upgrade
linux/Kernelto a version that resolves this vulnerability.Fixed in 7.1.5
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72254?
CVE-2026-72254 has a risk rating of 23.
What type of vulnerability is CVE-2026-72254?
CVE-2026-72254 is classified as a Null Pointer Dereference vulnerability.
How do I fix CVE-2026-72254?
To fix CVE-2026-72254, ensure your Linux kernel is updated to the latest version that resolves this issue.
What component is affected by CVE-2026-72254?
CVE-2026-72254 affects the netfilter component in the Linux kernel.
What can be exploited in CVE-2026-72254?
CVE-2026-72254 can be exploited via a fib expression in a netdev egress base chain that may lead to a NULL pointer dereference.