{"id":"CVE-2026-99042","title":"io_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6\n\nio_connect_bpf_populate() fills connect.port and connect.v6_addr for\nAF_INET6 only when addr_len …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 899bea8248cee35d54760a5e7d61a76af8e64411 < 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5","Linux >= 899bea8248cee35d54760a5e7d61a76af8e64411 < aa5d5f8e502318e783545ba5d04bb40130b83e20","Linux 7.2"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:22:01.804Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99042","references":[{"url":"https://git.kernel.org/stable/c/596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5"},{"url":"https://git.kernel.org/stable/c/aa5d5f8e502318e783545ba5d04bb40130b83e20"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.528Z","slug":"CVE-2026-99042","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: populate CONNECT filter fields for 24-byte sockaddr_in6\n\nio_connect_bpf_populate() fills connect.port and connect.v6_addr for\nAF_INET6 only when addr_len >= sizeof(struct sockaddr_in6), i.e. 28\nbytes.\n\nThe IPv6 connect paths accept SIN6_LEN_RFC2133 (24 bytes), which\nalready holds sin6_port and sin6_addr. io_connect() passes addr_len to\nthe socket layer unchanged.\n\nAt addr_len 24 the filter sees family AF_INET6 with port and address\nzero, while the kernel connects to the real destination. A filter that\ndenies an IPv6 port or address is bypassed. Denying connect.port == P\nrejects [::1]:P with -EACCES at addr_len 28 but connects at addr_len 24.\n\nUse SIN6_LEN_RFC2133 as the threshold. sin6_scope_id stays zero when\nabsent.\n\nThe threshold mismatch was found by an AI coding assistant (Claude Code)\ncomparing this hook against the net/ipv6 length checks on my\ninstructions; it also drafted the reproducer and this patch. I verified\nthe bypass and the fix in a VM on 7.3-rc6 and that 7.2 has the same\ncode.\n\n## Affected\n\n- `Linux >= 899bea8248cee35d54760a5e7d61a76af8e64411 < 596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5`\n- `Linux >= 899bea8248cee35d54760a5e7d61a76af8e64411 < aa5d5f8e502318e783545ba5d04bb40130b83e20`\n- `Linux 7.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}