{"id":"CVE-2026-45841","state":"PUBLISHED","title":"netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO\n\nnf_osf_match_one() computes ctx->window % f->wss.val in the\nOSF_WSS_MODULO branch with no guard for f->wss.val == 0. A\nCAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a\nsubsequent matching TCP SYN divides by zero and panics the kernel.\n\nReject the bogus fingerprint in nfnl_osf_add_callback() above the\nper-option for-loop. f->wss is per-fingerprint, not per-option, so\nthe check must run regardless of f->opt_num (including 0). Also\nreject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that\nas \"should not happen\".\n\nCrash:\n Oops: divide error: 0000 [#1] SMP KASAN NOPTI\n RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98)\n Call Trace:\n <IRQ>\n  nf_osf_match (net/netfilter/nfnetlink_osf.c:220)\n  xt_osf_match_packet (net/netfilter/xt_osf.c:32)\n  ipt_do_table (net/ipv4/netfilter/ip_tables.c:348)\n  nf_hook_slow (net/netfilter/core.c:622)\n  ip_local_deliver (net/ipv4/ip_input.c:265)\n  ip_rcv (include/linux/skbuff.h:1162)\n  __netif_receive_skb_one_core (net/core/dev.c:6181)\n  process_backlog (net/core/dev.c:6642)\n  __napi_poll (net/core/dev.c:7710)\n  net_rx_action (net/core/dev.c:7945)\n  handle_softirqs (kernel/softirq.c:622)","publishedAt":"2026-05-27T09:24:40.805Z","updatedAt":"2026-10-15T01:19:44.352Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"cb833bbc1b3c51e08652d3c86298307c07d3f2db","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"26900306a5a2c3e4f75c643a064525526bb6e5f3","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"0694618cf3e9b120666e31f5f383a6e466d95a0d","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"8def8fbd23f40e945febe913d04b731012ce0082","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"c55940895245d8ef658ab381248a28755218d625","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"9a05e195618a6d474f2bcd5b6376d0ffc2f00366","versionType":"git"},{"version":"11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384","status":"affected","lessThan":"2195574dc6d9017d32ac346987e12659f931d932","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nfnetlink_osf.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.31","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.31","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.141","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.91","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.33","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.10","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nfnetlink_osf.c"]}],"references":["https://git.kernel.org/stable/c/cb833bbc1b3c51e08652d3c86298307c07d3f2db","https://git.kernel.org/stable/c/26900306a5a2c3e4f75c643a064525526bb6e5f3","https://git.kernel.org/stable/c/0694618cf3e9b120666e31f5f383a6e466d95a0d","https://git.kernel.org/stable/c/8def8fbd23f40e945febe913d04b731012ce0082","https://git.kernel.org/stable/c/c55940895245d8ef658ab381248a28755218d625","https://git.kernel.org/stable/c/fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f","https://git.kernel.org/stable/c/9a05e195618a6d474f2bcd5b6376d0ffc2f00366","https://git.kernel.org/stable/c/2195574dc6d9017d32ac346987e12659f931d932","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45841.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45841","state":"PUBLISHED","datePublished":"2026-05-27T09:24:40.805Z","dateUpdated":"2026-10-15T01:19:44.352Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.078Z"},"containers":{"cna":{"title":"netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO\n\nnf_osf_match_one() computes ctx->window % f->wss.val in the\nOSF_WSS_MODULO branch with no guard for f->wss.val == 0. A\nCAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a\nsubsequent matching TCP SYN divides by zero and panics the kernel.\n\nReject the bogus fingerprint in nfnl_osf_add_callback() above the\nper-option for-loop. f->wss is per-fingerprint, not per-option, so\nthe check must run regardless of f->opt_num (including 0). Also\nreject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that\nas \"should not happen\".\n\nCrash:\n Oops: divide error: 0000 [#1] SMP KASAN NOPTI\n RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98)\n Call Trace:\n <IRQ>\n  nf_osf_match (net/netfilter/nfnetlink_osf.c:220)\n  xt_osf_match_packet (net/netfilter/xt_osf.c:32)\n  ipt_do_table (net/ipv4/netfilter/ip_tables.c:348)\n  nf_hook_slow (net/netfilter/core.c:622)\n  ip_local_deliver (net/ipv4/ip_input.c:265)\n  ip_rcv (include/linux/skbuff.h:1162)\n  __netif_receive_skb_one_core (net/core/dev.c:6181)\n  process_backlog (net/core/dev.c:6642)\n  __napi_poll (net/core/dev.c:7710)\n  net_rx_action (net/core/dev.c:7945)\n  handle_softirqs 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