{"schema":"threatline.record/2","record":{"id":"CVE-2026-98598","aliases":[],"summary":"ipv6: Prevent rt6_insert_exception() for dying fib6_info.","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: Prevent rt6_insert_exception() for dying fib6_info.\n\nBefore the cited commit, fib6_nh_flush_exceptions() always set\nfrom->exception_bucket_flushed = 1 under rt6_exception_lock to\nprevent rt6_insert_exception() from inserting a new exception\nfor a dying fib6_info.\n\nThe flag was replaced with the FIB6_EXCEPTION_BUCKET_FLUSHED\nbit stored in nh->rt6i_exception_bucket.\n\nThe problem is that now the bit is only set when the bucket\nis not NULL and fib6_nh_flush_exceptions() is called from\nfib6_nh_release() after fib6_ref has already reached zero.\n\nIf rt6_insert_exception() is called while the target fib6_info\nis being removed via fib6_purge_rt(), a new exception could be\ncreated successfully because rt6_flush_exceptions() no longer\nsets the bit.\n\nThis creates a reference cycle between the fib6_info and the\nexception route, leaking the fib6_info, its nexthop device,\nand all per-CPU routes in fib6_nh->rt6i_pcpu, which stalls netdev\nunregistration.\n\n[   34.680602] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[   44.920675] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[   55.176582] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n\nLet's call fib6_drop_pcpu_from() before rt6_flush_exceptions(),\nto set fib6_destroying before rt6_exception_lock, and check\nf6i->fib6_destroying in rt6_insert_exception().\n\nNote that FIB6_EXCEPTION_BUCKET_FLUSHED logic is dead and\nwe can clean it up in net-next.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98598","source_modified_at":"2026-10-19T09:22:24.055Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"cc5c073a693fa6ed7a207b0436114f68cce72434","lessThan":"649ffc76ed5483b2caf35ed90d3787538efc4e53","status":"affected","versionType":"git"},{"version":"cc5c073a693fa6ed7a207b0436114f68cce72434","lessThan":"e03e77071e75ce726d877f0a4349a28b6e1f487a","status":"affected","versionType":"git"},{"version":"cc5c073a693fa6ed7a207b0436114f68cce72434","lessThan":"0346ec2f080b40d95ed05b853bb9226289e75212","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98598","source_modified_at":"2026-10-19T09:22:24.055Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.3","status":"affected"},{"version":"0","lessThan":"5.3","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98598","source_modified_at":"2026-10-19T09:22:24.055Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"649ffc76ed5483b2caf35ed90d3787538efc4e53","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98598","source_modified_at":"2026-10-19T09:22:24.055Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"0346ec2f080b40d95ed05b853bb9226289e75212","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00198,"percentile":0.09056,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:19:11.126Z","modified_at":"2026-10-19T09:22:24.055Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98598","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:22:24.055Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98598","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/649ffc76ed5483b2caf35ed90d3787538efc4e53"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/e03e77071e75ce726d877f0a4349a28b6e1f487a"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/0346ec2f080b40d95ed05b853bb9226289e75212"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:22:24.055Z","content_hash":"37f3935ddae3132641d143c9edc176b261e64614f74e9152106b5ea3e22a5dbc"}}