CVE-2026-31424netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP
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In the Linux kernel, the following vulnerability has been resolved: netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP Weiming Shi says: xt_match and xt_target structs registered with NFPROTO_UNSPEC can be loaded by any protocol family through nft_compat. When such a match/target sets .hooks to restrict which hooks it may run on, the bitmask uses NF_INET_* constants. This is only correct for families whose hook layout matches NF_INET_*: IPv4, IPv6, INET, and bridge all share the same five hooks (PRE_ROUTING ... POST_ROUTING). ARP only has three hooks (IN=0, OUT=1, FORWARD=2) with different semantics. Because NF_ARP_OUT == 1 == NF_INET_LOCAL_IN, the .hooks validation silently passes for the wrong reasons, allowing matches to run on ARP chains where the hook assumptions (e.g. state->in being set on input hooks) do not hold. This leads to NULL pointer dereferences; xt_devgroup is one concrete example: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000044: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000220-0x0000000000000227] RIP: 0010:devgroup_mt+0xff/0x350 Call Trace: <TASK> nft_match_eval (net/netfilter/nft_compat.c:407) nft_do_chain (net/netfilter/nf_tables_core.c:285) nft_do_chain_arp (net/netfilter/nft_chain_filter.c:61) nf_hook_slow (net/netfilter/core.c:623) arp_xmit (net/ipv4/arp.c:666) </TASK> Kernel panic - not syncing: Fatal exception in interrupt Fix it by restricting arptables to NFPROTO_ARP extensions only. Note that arptables-legacy only supports: - arpt_CLASSIFY - arpt_mangle - arpt_MARK that provide explicit NFPROTO_ARP match/target declarations.
- CVSS
- 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 9291747f118d6404e509747b85ff5f6dfec368d2 builds before 80e3c75f71c3ea1e62fcb032382de13e00a68f8b; from 9291747f118d6404e509747b85ff5f6dfec368d2 before d9a0af9e43416aa50c0595e15fa01365a1c72c49; 9291747f118d6404e509747b85ff5f6dfec368d2 builds before 1cd6313c8644bfebbd813a05da9daa21b09dd68c; from 9291747f118d6404e509747b85ff5f6dfec368d2 before f00ac65c90ea475719e08d629e2e26c8b4e6999b; from 9291747f118d6404e509747b85ff5f6dfec368d2 before e7e1b6bcb389c8708003d40613a59ff2496f6b1f; from 9291747f118d6404e509747b85ff5f6dfec368d2 before dc3e27dd7d76e21106b8f9bbdc31f5da74a89014; 9291747f118d6404e509747b85ff5f6dfec368d2 builds before 3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a; 9291747f118d6404e509747b85ff5f6dfec368d2 builds before 3d5d488f11776738deab9da336038add95d342d1 | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 2.6.39 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.168; from 6.2 before 6.6.134; from 6.7 before 6.12.81; from 6.13 before 6.18.22; from 6.19 before 6.19.12; 7.0; and 5 more ranges | NVD |
References
- https://git.kernel.org/stable/c/80e3c75f71c3ea1e62fcb032382de13e00a68f8bpatch
- https://git.kernel.org/stable/c/d9a0af9e43416aa50c0595e15fa01365a1c72c49patch
- https://git.kernel.org/stable/c/1cd6313c8644bfebbd813a05da9daa21b09dd68cpatch
- https://git.kernel.org/stable/c/f00ac65c90ea475719e08d629e2e26c8b4e6999bpatch
- https://git.kernel.org/stable/c/e7e1b6bcb389c8708003d40613a59ff2496f6b1fpatch
- https://git.kernel.org/stable/c/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014patch
- https://git.kernel.org/stable/c/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28apatch
- https://git.kernel.org/stable/c/3d5d488f11776738deab9da336038add95d342d1patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.