{"id":"CVE-2026-72254","summary":"netfilter: nft_fib: reject fib expression on the netdev egress hook","details":"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, 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.","modified":"2026-08-18T03:56:22.936317276Z","published":"2026-08-15T05:54:42.239Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72254.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4fee43759b489559a491f7c95f9bfa7a1d0c7a10"},{"type":"WEB","url":"https://git.kernel.org/stable/c/568931f26af4727a51e8521f72efbc78d3b82410"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d01c913febead04a01a5f3a6374d1f45504dc523"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d07955dd34ecae17d35d8c7d0a273a3fba653a8c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f68305267ebda7e839b5e8f77e8d77535a3d5a0f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72254.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72254"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"42df6e1d221dddc0f2acf2be37e68d553ad65f96"},{"fixed":"4fee43759b489559a491f7c95f9bfa7a1d0c7a10"},{"fixed":"568931f26af4727a51e8521f72efbc78d3b82410"},{"fixed":"d01c913febead04a01a5f3a6374d1f45504dc523"},{"fixed":"f68305267ebda7e839b5e8f77e8d77535a3d5a0f"},{"fixed":"d07955dd34ecae17d35d8c7d0a273a3fba653a8c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72254.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.6.148"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.101"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.42"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72254.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}