{"id":"CVE-2026-99072","title":"ipv4: stop route notification sizing when nexthop group shrinks","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: stop route notification sizing when nexthop group shrinks\n\nCommit 680aea08e78c (\"net: ipv4: Emit notification when fib\nhardware flags are changed\") added an RCU-o…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < 72d9d17092bb37b0717f12042a0817d01a1f9e78","Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54","Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49","Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88","Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < d3daa33c7af92e38f2274bbd2576f58bfbaf89e6","Linux 5.12"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:23:15.735Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99072","references":[{"url":"https://git.kernel.org/stable/c/72d9d17092bb37b0717f12042a0817d01a1f9e78"},{"url":"https://git.kernel.org/stable/c/ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54"},{"url":"https://git.kernel.org/stable/c/c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49"},{"url":"https://git.kernel.org/stable/c/ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88"},{"url":"https://git.kernel.org/stable/c/d3daa33c7af92e38f2274bbd2576f58bfbaf89e6"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.515Z","slug":"CVE-2026-99072","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nipv4: stop route notification sizing when nexthop group shrinks\n\nCommit 680aea08e78c (\"net: ipv4: Emit notification when fib\nhardware flags are changed\") added an RCU-only fib_nlmsg_size() call\nfor asynchronous hardware flag notifications.\n\nfib_nlmsg_size() checks fib_info_num_path() before each iteration,\nthen fib_info_nhc() independently reloads nh->nh_grp. If\nRTM_NEWNEXTHOP replaces a group with fewer paths between those loads,\nfib_info_nhc() returns NULL and fib_nexthop_nlmsg_size() dereferences\nit.\n\nStop sizing when the indexed path is absent. Nexthop groups are\ndense, so the current snapshot has no later path.\n\n## Affected\n\n- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < 72d9d17092bb37b0717f12042a0817d01a1f9e78`\n- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54`\n- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49`\n- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88`\n- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < d3daa33c7af92e38f2274bbd2576f58bfbaf89e6`\n- `Linux 5.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}