{"id":"CVE-2026-99072","state":"PUBLISHED","title":"ipv4: stop route notification sizing when nexthop group shrinks","description":"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-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.","publishedAt":"2026-10-23T12:23:15.735Z","updatedAt":"2026-10-30T12:41:31.995Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"96f3fbb8575593657c7e80786dc3251d2fe3931b","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"81f0deb02a5b5477f236bbbaed1149b779a8632b","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"72d9d17092bb37b0717f12042a0817d01a1f9e78","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"d3daa33c7af92e38f2274bbd2576f58bfbaf89e6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/fib_semantics.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.12","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/fib_semantics.c"]}],"references":["https://git.kernel.org/stable/c/96f3fbb8575593657c7e80786dc3251d2fe3931b","https://git.kernel.org/stable/c/81f0deb02a5b5477f236bbbaed1149b779a8632b","https://git.kernel.org/stable/c/72d9d17092bb37b0717f12042a0817d01a1f9e78","https://git.kernel.org/stable/c/ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54","https://git.kernel.org/stable/c/c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49","https://git.kernel.org/stable/c/ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88","https://git.kernel.org/stable/c/d3daa33c7af92e38f2274bbd2576f58bfbaf89e6"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99072.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99072","state":"PUBLISHED","datePublished":"2026-10-23T12:23:15.735Z","dateUpdated":"2026-10-30T12:41:31.995Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.389Z"},"containers":{"cna":{"title":"ipv4: stop route notification sizing when nexthop group shrinks","descriptions":[{"lang":"en","value":"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-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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"96f3fbb8575593657c7e80786dc3251d2fe3931b","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"81f0deb02a5b5477f236bbbaed1149b779a8632b","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"72d9d17092bb37b0717f12042a0817d01a1f9e78","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"ad1c9f1b98c92609e9bb2ae8f05916defc3b0a54","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"c1f48d1c2d5e9efd904dbbc2f2b3d41543e55c49","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"ad2b3a68b8a7d5d27de88e05674e4adb1ce46d88","versionType":"git"},{"version":"680aea08e78c003292415518ad270bc20f9c80b1","status":"affected","lessThan":"d3daa33c7af92e38f2274bbd2576f58bfbaf89e6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/fib_semantics.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.12","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv4/fib_semantics.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/96f3fbb8575593657c7e80786dc3251d2fe3931b"},{"url":"https://git.kernel.org/stable/c/81f0deb02a5b5477f236bbbaed1149b779a8632b"},{"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:41:31.995Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"7.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}