{"id":"CVE-2026-98485","state":"PUBLISHED","title":"netfilter: ip6t_rt: fix zero-address non-strict match out-of-bounds read","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ip6t_rt: fix zero-address non-strict match out-of-bounds read\n\nrt_mt6_check() permits rules to be configured with rtinfo->addrnr == 0\neven when address matching (IP6T_RT_FST_MASK) is requested.\n\nIn the IP6T_RT_FST_NSTRICT path, rt_mt6() evaluates packet routing\naddresses against rtinfo->addrs[i] and terminates backwards at the bottom\nof the loop:\n\n    if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {\n        i++;\n    }\n    if (i == rtinfo->addrnr)\n        break;\n\nWhen addrnr is 0, if the first packet address matches rtinfo->addrs[0],\ni is incremented to 1. Because i is now strictly greater than addrnr (0),\nthe loop termination condition (i == rtinfo->addrnr) is bypassed and will\nnever be satisfied.\n\nIf a crafted IPv6 packet contains matching routing addresses, i will\nadvance past IP6T_RT_HOPS (16). The subsequent call to ipv6_addr_equal()\nreads beyond struct ip6t_rt, triggering UBSAN/KASAN out-of-bounds warnings\nor kernel panics.\n\nFix this by:\n1. Rejecting rules in rt_mt6_check() where IP6T_RT_FST_MASK is set but\n   rtinfo->addrnr is zero.\n2. In rt_mt6(), moving the termination condition (i < rtinfo->addrnr)\n   into the for-loop header condition and removing the backwards break\n   at the end of the loop body.","publishedAt":"2026-10-18T15:16:00.435Z","updatedAt":"2026-10-24T14:09:02.897Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"959d1829d1ce8b91b435b24a923b51bcc8897090","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"fe336bab13834394320997de8b16ca4a913b4f13","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5a54f8b7f7fe207a5c14713015a5820588faf1ad","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"b89249819a7d6698bed152feafd3bc6c08489d15","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"dd55c0ea87bf70e4e4b3b683acd29ef981335b26","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"191239b0939692e92459d8d32cad14247fa93f89","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"d9cf4ac6f326330e1fe4d95671d36a6ff3593f64","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"82313c169eddc02b1bf5ba6b427803e272d3ec42","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/netfilter/ip6t_rt.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/netfilter/ip6t_rt.c"]}],"references":["https://git.kernel.org/stable/c/959d1829d1ce8b91b435b24a923b51bcc8897090","https://git.kernel.org/stable/c/fe336bab13834394320997de8b16ca4a913b4f13","https://git.kernel.org/stable/c/5a54f8b7f7fe207a5c14713015a5820588faf1ad","https://git.kernel.org/stable/c/b89249819a7d6698bed152feafd3bc6c08489d15","https://git.kernel.org/stable/c/dd55c0ea87bf70e4e4b3b683acd29ef981335b26","https://git.kernel.org/stable/c/191239b0939692e92459d8d32cad14247fa93f89","https://git.kernel.org/stable/c/d9cf4ac6f326330e1fe4d95671d36a6ff3593f64","https://git.kernel.org/stable/c/82313c169eddc02b1bf5ba6b427803e272d3ec42"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98485.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98485","state":"PUBLISHED","datePublished":"2026-10-18T15:16:00.435Z","dateUpdated":"2026-10-24T14:09:02.897Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.352Z"},"containers":{"cna":{"title":"netfilter: ip6t_rt: fix zero-address non-strict match out-of-bounds read","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ip6t_rt: fix zero-address non-strict match out-of-bounds read\n\nrt_mt6_check() permits rules to be configured with rtinfo->addrnr == 0\neven when address matching (IP6T_RT_FST_MASK) is requested.\n\nIn the IP6T_RT_FST_NSTRICT path, rt_mt6() evaluates packet routing\naddresses against rtinfo->addrs[i] and terminates backwards at the bottom\nof the loop:\n\n    if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {\n        i++;\n    }\n    if (i == rtinfo->addrnr)\n        break;\n\nWhen addrnr is 0, if the first packet address matches rtinfo->addrs[0],\ni is incremented to 1. Because i is now strictly greater than addrnr (0),\nthe loop termination condition (i == rtinfo->addrnr) is bypassed and will\nnever be satisfied.\n\nIf a crafted IPv6 packet contains matching routing addresses, i will\nadvance past IP6T_RT_HOPS (16). The subsequent call to ipv6_addr_equal()\nreads beyond struct ip6t_rt, triggering UBSAN/KASAN out-of-bounds warnings\nor kernel panics.\n\nFix this by:\n1. Rejecting rules in rt_mt6_check() where IP6T_RT_FST_MASK is set but\n   rtinfo->addrnr is zero.\n2. In rt_mt6(), moving the termination condition (i < rtinfo->addrnr)\n   into the for-loop header condition and removing the backwards break\n   at the end of the loop body."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"959d1829d1ce8b91b435b24a923b51bcc8897090","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"fe336bab13834394320997de8b16ca4a913b4f13","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5a54f8b7f7fe207a5c14713015a5820588faf1ad","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"b89249819a7d6698bed152feafd3bc6c08489d15","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"dd55c0ea87bf70e4e4b3b683acd29ef981335b26","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"191239b0939692e92459d8d32cad14247fa93f89","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"d9cf4ac6f326330e1fe4d95671d36a6ff3593f64","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"82313c169eddc02b1bf5ba6b427803e272d3ec42","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/netfilter/ip6t_rt.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/netfilter/ip6t_rt.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/959d1829d1ce8b91b435b24a923b51bcc8897090"},{"url":"https://git.kernel.org/stable/c/fe336bab13834394320997de8b16ca4a913b4f13"},{"url":"https://git.kernel.org/stable/c/5a54f8b7f7fe207a5c14713015a5820588faf1ad"},{"url":"https://git.kernel.org/stable/c/b89249819a7d6698bed152feafd3bc6c08489d15"},{"url":"https://git.kernel.org/stable/c/dd55c0ea87bf70e4e4b3b683acd29ef981335b26"},{"url":"https://git.kernel.org/stable/c/191239b0939692e92459d8d32cad14247fa93f89"},{"url":"https://git.kernel.org/stable/c/d9cf4ac6f326330e1fe4d95671d36a6ff3593f64"},{"url":"https://git.kernel.org/stable/c/82313c169eddc02b1bf5ba6b427803e272d3ec42"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bad state enters through local setsockopt(IP6T_SO_SET_REPLACE) or NFT_MSG_NEWRULE rule installation; ip6_rcv then reaches rt_mt6 through NF_INET_PRE_ROUTING and ip6t_do_table. A remote packet alone cannot create the required zero-address rule.\nAC:L - The attacker controls the rule's addrs[] despite addrnr being zero and can send a 17-address routing header whose first 16 addresses match, making rt_mt6 deterministically read addrs[16]. No race or external timing condition is required.\nPR:L - do_ip6t_set_ctl requires ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN), while nfnetlink uses netlink_net_capable; an unprivileged user can satisfy either check in a user-created user and network namespace.\nUI:N - The attacker installs the malformed rule and injects the triggering IPv6 packet through their own syscalls. No action by another user is needed.\nS:U - The invalid read occurs during netfilter rule evaluation inside the same host kernel security authority. It does not cross a VM, IOMMU, or comparable scope boundary.\nC:H - ipv6_addr_equal() reads 16 bytes from each selected &rtinfo->addrs[i], and rt_mt6 can advance beyond the fixed 16-entry array across up to 127 routing-header address iterations. The overread is therefore not strictly bounded to a few bytes.\nI:N - rt_mt6 only fetches the out-of-bounds address for comparison and updates its local index; it performs no out-of-bounds write or other memory modification.\nA:H - At i == 16, the fixed-array subscript and 16-byte ipv6_addr_equal() load trigger UBSAN/KASAN out-of-bounds handling and can panic the kernel, as documented by the fix. The attacker can repeat the rule-and-packet sequence without a race."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-24T14:09:02.897Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}