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ubuntu-cve-2026-45841
Vulnerability from osv_ubuntu
Published
2026-05-27 11:16
Modified
2026-09-09 12:03
Summary
Details

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: 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
References
https://ubuntu.com/security/CVE-2026-45841 REPORT
https://www.cve.org/CVERecord?id=CVE-2026-45841 REPORT
https://git.kernel.org/linus/2195574dc6d9017d32ac… REPORT
https://ubuntu.com/security/notices/USN-8566-1 ADVISORY
https://ubuntu.com/security/notices/USN-8568-1 ADVISORY
https://ubuntu.com/security/notices/USN-8569-1 ADVISORY
https://ubuntu.com/security/notices/USN-8567-1 ADVISORY
https://ubuntu.com/security/notices/USN-8574-1 ADVISORY
https://ubuntu.com/security/notices/USN-8575-1 ADVISORY
https://ubuntu.com/security/notices/USN-8576-1 ADVISORY
https://ubuntu.com/security/notices/USN-8593-1 ADVISORY
https://ubuntu.com/security/notices/USN-8574-2 ADVISORY
https://ubuntu.com/security/notices/USN-8595-1 ADVISORY
https://ubuntu.com/security/notices/USN-8596-1 ADVISORY
https://ubuntu.com/security/notices/USN-8575-2 ADVISORY
https://ubuntu.com/security/notices/USN-8576-2 ADVISORY
https://ubuntu.com/security/notices/USN-8603-1 ADVISORY
https://ubuntu.com/security/notices/USN-8595-2 ADVISORY
https://ubuntu.com/security/notices/USN-8606-1 ADVISORY
https://ubuntu.com/security/notices/USN-8607-1 ADVISORY
https://ubuntu.com/security/notices/USN-8608-1 ADVISORY
https://ubuntu.com/security/notices/USN-8609-1 ADVISORY
https://ubuntu.com/security/notices/USN-8575-3 ADVISORY
https://ubuntu.com/security/notices/USN-8610-1 ADVISORY
https://ubuntu.com/security/notices/USN-8618-1 ADVISORY
https://ubuntu.com/security/notices/USN-8574-3 ADVISORY
https://ubuntu.com/security/notices/USN-8595-3 ADVISORY
https://ubuntu.com/security/notices/USN-8619-1 ADVISORY
https://ubuntu.com/security/notices/USN-8620-1 ADVISORY
https://ubuntu.com/security/notices/USN-8620-2 ADVISORY
https://ubuntu.com/security/notices/USN-8620-3 ADVISORY
https://ubuntu.com/security/notices/USN-8620-4 ADVISORY
https://ubuntu.com/security/notices/USN-8663-1 ADVISORY
https://ubuntu.com/security/notices/USN-8664-1 ADVISORY
https://ubuntu.com/security/notices/USN-8665-1 ADVISORY
https://ubuntu.com/security/notices/USN-8668-1 ADVISORY
https://ubuntu.com/security/notices/USN-8728-1 ADVISORY

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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.

Sightings

Author Source Type Date Other

Nomenclature

  • 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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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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