{"id":"CVE-2026-31424","state":"PUBLISHED","title":"netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP\n\nWeiming Shi says:\n\nxt_match and xt_target structs registered with NFPROTO_UNSPEC can be\nloaded by any protocol family through nft_compat. When such a\nmatch/target sets .hooks to restrict which hooks it may run on, the\nbitmask uses NF_INET_* constants. This is only correct for families\nwhose hook layout matches NF_INET_*: IPv4, IPv6, INET, and bridge\nall share the same five hooks (PRE_ROUTING ... POST_ROUTING).\n\nARP only has three hooks (IN=0, OUT=1, FORWARD=2) with different\nsemantics. Because NF_ARP_OUT == 1 == NF_INET_LOCAL_IN, the .hooks\nvalidation silently passes for the wrong reasons, allowing matches to\nrun on ARP chains where the hook assumptions (e.g. state->in being\nset on input hooks) do not hold. This leads to NULL pointer\ndereferences; xt_devgroup is one concrete example:\n\n Oops: general protection fault, probably for non-canonical address 0xdffffc0000000044: 0000 [#1] SMP KASAN NOPTI\n KASAN: null-ptr-deref in range [0x0000000000000220-0x0000000000000227]\n RIP: 0010:devgroup_mt+0xff/0x350\n Call Trace:\n  <TASK>\n  nft_match_eval (net/netfilter/nft_compat.c:407)\n  nft_do_chain (net/netfilter/nf_tables_core.c:285)\n  nft_do_chain_arp (net/netfilter/nft_chain_filter.c:61)\n  nf_hook_slow (net/netfilter/core.c:623)\n  arp_xmit (net/ipv4/arp.c:666)\n  </TASK>\n Kernel panic - not syncing: Fatal exception in interrupt\n\nFix it by restricting arptables to NFPROTO_ARP extensions only.\nNote that arptables-legacy only supports:\n\n- arpt_CLASSIFY\n- arpt_mangle\n- arpt_MARK\n\nthat provide explicit NFPROTO_ARP match/target declarations.","publishedAt":"2026-04-13T13:40:27.957Z","updatedAt":"2026-10-15T01:16:06.312Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"80e3c75f71c3ea1e62fcb032382de13e00a68f8b","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"d9a0af9e43416aa50c0595e15fa01365a1c72c49","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"1cd6313c8644bfebbd813a05da9daa21b09dd68c","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"f00ac65c90ea475719e08d629e2e26c8b4e6999b","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"e7e1b6bcb389c8708003d40613a59ff2496f6b1f","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"dc3e27dd7d76e21106b8f9bbdc31f5da74a89014","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"3d5d488f11776738deab9da336038add95d342d1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/x_tables.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.39","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.39","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.134","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/x_tables.c"]}],"references":["https://git.kernel.org/stable/c/80e3c75f71c3ea1e62fcb032382de13e00a68f8b","https://git.kernel.org/stable/c/d9a0af9e43416aa50c0595e15fa01365a1c72c49","https://git.kernel.org/stable/c/1cd6313c8644bfebbd813a05da9daa21b09dd68c","https://git.kernel.org/stable/c/f00ac65c90ea475719e08d629e2e26c8b4e6999b","https://git.kernel.org/stable/c/e7e1b6bcb389c8708003d40613a59ff2496f6b1f","https://git.kernel.org/stable/c/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014","https://git.kernel.org/stable/c/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a","https://git.kernel.org/stable/c/3d5d488f11776738deab9da336038add95d342d1","https://cert-portal.siemens.com/productcert/html/ssa-082556.html","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31424.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31424","state":"PUBLISHED","datePublished":"2026-04-13T13:40:27.957Z","dateUpdated":"2026-10-15T01:16:06.312Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.088Z"},"containers":{"cna":{"title":"netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP\n\nWeiming Shi says:\n\nxt_match and xt_target structs registered with NFPROTO_UNSPEC can be\nloaded by any protocol family through nft_compat. When such a\nmatch/target sets .hooks to restrict which hooks it may run on, the\nbitmask uses NF_INET_* constants. This is only correct for families\nwhose hook layout matches NF_INET_*: IPv4, IPv6, INET, and bridge\nall share the same five hooks (PRE_ROUTING ... POST_ROUTING).\n\nARP only has three hooks (IN=0, OUT=1, FORWARD=2) with different\nsemantics. Because NF_ARP_OUT == 1 == NF_INET_LOCAL_IN, the .hooks\nvalidation silently passes for the wrong reasons, allowing matches to\nrun on ARP chains where the hook assumptions (e.g. state->in being\nset on input hooks) do not hold. This leads to NULL pointer\ndereferences; xt_devgroup is one concrete example:\n\n Oops: general protection fault, probably for non-canonical address 0xdffffc0000000044: 0000 [#1] SMP KASAN NOPTI\n KASAN: null-ptr-deref in range [0x0000000000000220-0x0000000000000227]\n RIP: 0010:devgroup_mt+0xff/0x350\n Call Trace:\n  <TASK>\n  nft_match_eval (net/netfilter/nft_compat.c:407)\n  nft_do_chain (net/netfilter/nf_tables_core.c:285)\n  nft_do_chain_arp (net/netfilter/nft_chain_filter.c:61)\n  nf_hook_slow (net/netfilter/core.c:623)\n  arp_xmit (net/ipv4/arp.c:666)\n  </TASK>\n Kernel panic - not syncing: Fatal exception in interrupt\n\nFix it by restricting arptables to NFPROTO_ARP extensions only.\nNote that arptables-legacy only supports:\n\n- arpt_CLASSIFY\n- arpt_mangle\n- arpt_MARK\n\nthat provide explicit NFPROTO_ARP match/target declarations."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"80e3c75f71c3ea1e62fcb032382de13e00a68f8b","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"d9a0af9e43416aa50c0595e15fa01365a1c72c49","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"1cd6313c8644bfebbd813a05da9daa21b09dd68c","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"f00ac65c90ea475719e08d629e2e26c8b4e6999b","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"e7e1b6bcb389c8708003d40613a59ff2496f6b1f","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"dc3e27dd7d76e21106b8f9bbdc31f5da74a89014","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a","versionType":"git"},{"version":"9291747f118d6404e509747b85ff5f6dfec368d2","status":"affected","lessThan":"3d5d488f11776738deab9da336038add95d342d1","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/x_tables.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.39","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.39","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.134","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.81","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.22","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.12","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/x_tables.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/80e3c75f71c3ea1e62fcb032382de13e00a68f8b"},{"url":"https://git.kernel.org/stable/c/d9a0af9e43416aa50c0595e15fa01365a1c72c49"},{"url":"https://git.kernel.org/stable/c/1cd6313c8644bfebbd813a05da9daa21b09dd68c"},{"url":"https://git.kernel.org/stable/c/f00ac65c90ea475719e08d629e2e26c8b4e6999b"},{"url":"https://git.kernel.org/stable/c/e7e1b6bcb389c8708003d40613a59ff2496f6b1f"},{"url":"https://git.kernel.org/stable/c/dc3e27dd7d76e21106b8f9bbdc31f5da74a89014"},{"url":"https://git.kernel.org/stable/c/3e79374b03bf9a2f282f0eb1d0ac3776f7e0f28a"},{"url":"https://git.kernel.org/stable/c/3d5d488f11776738deab9da336038add95d342d1"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T22:08:26.363Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"6.1.168"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"6.6.134"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"6.12.81"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"6.18.22"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"6.19.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.39","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC 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