Answer in brief
CVE-2026-45841 records a Medium severity (CVSS 5.5) vulnerability in netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <cb833bbc1b3c51e08652d3c86298307c07d3f2db || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <26900306a5a2c3e4f75c643a064525526bb6e5f3 || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <0694618cf3e9b120666e31f5f383a6e466d95a0d || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <8def8fbd23f40e945febe913d04b731012ce0082 || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <c55940895245d8ef658ab381248a28755218d625 || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <9a05e195618a6d474f2bcd5b6376d0ffc2f00366 || >=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <2195574dc6d9017d32ac346987e12659f931d932 | cb833bbc1b3c51e08652d3c86298307c07d3f2db, 26900306a5a2c3e4f75c643a064525526bb6e5f3, 0694618cf3e9b120666e31f5f383a6e466d95a0d, 8def8fbd23f40e945febe913d04b731012ce0082, c55940895245d8ef658ab381248a28755218d625, fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f, 9a05e195618a6d474f2bcd5b6376d0ffc2f00366, 2195574dc6d9017d32ac346987e12659f931d932 |
| Linux/Linuxgeneric | 2.6.31 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 26, 2026
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)
Quoted source text, attributed separately from HOL analysis.