CVE-2026-45841 (GCVE-0-2026-45841)

Vulnerability from cvelistv5 – Published: 2026-05-27 09:24 – Updated: 2026-05-27 09:24
VLAI
Title
netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO nf_osf_match_one() computes ctx->window % f->wss.val in the OSF_WSS_MODULO branch with no guard for f->wss.val == 0. A CAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a subsequent matching TCP SYN divides by zero and panics the kernel. Reject the bogus fingerprint in nfnl_osf_add_callback() above the per-option for-loop. f->wss is per-fingerprint, not per-option, so the check must run regardless of f->opt_num (including 0). Also reject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that as "should not happen". Crash: Oops: divide error: 0000 [#1] SMP KASAN NOPTI RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98) Call Trace: <IRQ> nf_osf_match (net/netfilter/nfnetlink_osf.c:220) xt_osf_match_packet (net/netfilter/xt_osf.c:32) ipt_do_table (net/ipv4/netfilter/ip_tables.c:348) nf_hook_slow (net/netfilter/core.c:622) ip_local_deliver (net/ipv4/ip_input.c:265) ip_rcv (include/linux/skbuff.h:1162) __netif_receive_skb_one_core (net/core/dev.c:6181) process_backlog (net/core/dev.c:6642) __napi_poll (net/core/dev.c:7710) net_rx_action (net/core/dev.c:7945) handle_softirqs (kernel/softirq.c:622)
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 , < 8def8fbd23f40e945febe913d04b731012ce0082 (git)
Affected: 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 , < c55940895245d8ef658ab381248a28755218d625 (git)
Affected: 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 , < fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f (git)
Affected: 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 , < 9a05e195618a6d474f2bcd5b6376d0ffc2f00366 (git)
Affected: 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 , < 2195574dc6d9017d32ac346987e12659f931d932 (git)
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Linux Linux Affected: 2.6.31
Unaffected: 0 , < 2.6.31 (semver)
Unaffected: 6.6.141 , ≤ 6.6.* (semver)
Unaffected: 6.12.91 , ≤ 6.12.* (semver)
Unaffected: 6.18.33 , ≤ 6.18.* (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1-rc1 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
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          "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-\u003ewindow % f-\u003ewss.val in the\nOSF_WSS_MODULO branch with no guard for f-\u003ewss.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-\u003ewss is per-fingerprint, not per-option, so\nthe check must run regardless of f-\u003eopt_num (including 0). Also\nreject wss.wc \u003e= 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 \u003cIRQ\u003e\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)"
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      "title": "netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO",
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    "cveId": "CVE-2026-45841",
    "datePublished": "2026-05-27T09:24:40.805Z",
    "dateReserved": "2026-05-13T15:03:33.078Z",
    "dateUpdated": "2026-05-27T09:24:40.805Z",
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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