{"id":"CVE-2026-72254","title":"netfilter: nft_fib: reject fib expression on the netdev egress hook","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_fib: reject fib expression on the netdev egress hook\n\nA fib expression in a netdev egress base chain dereferences nft_in(pkt),\nNULL on the transmit path,…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < 4fee43759b489559a491f7c95f9bfa7a1d0c7a10","Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < 568931f26af4727a51e8521f72efbc78d3b82410","Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < d01c913febead04a01a5f3a6374d1f45504dc523","Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < f68305267ebda7e839b5e8f77e8d77535a3d5a0f","Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < d07955dd34ecae17d35d8c7d0a273a3fba653a8c","Linux 5.16"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T18:45:20.670806Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:13.693Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72254","references":[{"url":"https://git.kernel.org/stable/c/4fee43759b489559a491f7c95f9bfa7a1d0c7a10"},{"url":"https://git.kernel.org/stable/c/568931f26af4727a51e8521f72efbc78d3b82410"},{"url":"https://git.kernel.org/stable/c/d01c913febead04a01a5f3a6374d1f45504dc523"},{"url":"https://git.kernel.org/stable/c/f68305267ebda7e839b5e8f77e8d77535a3d5a0f"},{"url":"https://git.kernel.org/stable/c/d07955dd34ecae17d35d8c7d0a273a3fba653a8c"}],"tags":["cve.org"],"epss":0.00612,"epssPercentile":0.48207,"ingestedAt":"2026-10-16T19:46:24.415Z","slug":"CVE-2026-72254","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_fib: reject fib expression on the netdev egress hook\n\nA fib expression in a netdev egress base chain dereferences nft_in(pkt),\nNULL on the transmit path, causing a NULL pointer dereference at eval.\nnft_fib_validate() masks the hook with NF_INET_* values, but netdev hook\nnumbers are a separate enum that aliases them (NF_NETDEV_EGRESS ==\nNF_INET_LOCAL_IN), so an egress chain passes validation and then faults.\n\nAdd nft_fib_netdev_validate() that limits each result/flag to the netdev\nhook where the device it reads exists: the input-device cases (OIF,\nOIFNAME, ADDRTYPE with F_IIF) to ingress, the output-device case (ADDRTYPE\nwith F_OIF) to egress, ADDRTYPE with no device flag to both. Also restrict\nnft_fib_validate() to NFPROTO_IPV4/IPV6/INET so its NF_INET_* masks are\nnot applied to another family's hooks.\n\n## Affected\n\n- `Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < 4fee43759b489559a491f7c95f9bfa7a1d0c7a10`\n- `Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < 568931f26af4727a51e8521f72efbc78d3b82410`\n- `Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < d01c913febead04a01a5f3a6374d1f45504dc523`\n- `Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < f68305267ebda7e839b5e8f77e8d77535a3d5a0f`\n- `Linux >= 42df6e1d221dddc0f2acf2be37e68d553ad65f96 < d07955dd34ecae17d35d8c7d0a273a3fba653a8c`\n- `Linux 5.16`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}