{"id":"CVE-2026-31682","state":"PUBLISHED","title":"bridge: br_nd_send: linearize skb before parsing ND options","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: br_nd_send: linearize skb before parsing ND options\n\nbr_nd_send() parses neighbour discovery options from ns->opt[] and\nassumes that these options are in the linear part of request.\n\nIts callers only guarantee that the ICMPv6 header and target address\nare available, so the option area can still be non-linear. Parsing\nns->opt[] in that case can access data past the linear buffer.\n\nLinearize request before option parsing and derive ns from the linear\nnetwork header.","publishedAt":"2026-04-25T08:46:59.106Z","updatedAt":"2026-10-19T18:56:04.675Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/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":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"c68433fd291c9e88c00292095172c62d1997d662","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"4f397b950c916e9a1f8a4fce04ea0110206cad47","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"bd91ec85aa4c77d645bd2739fc56784157a88ca2","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"658261898130da620fc3d0fbb0523efb3366cb55","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"2ba4caba423ed94d63006eb1d2227b0332ab7fcd","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"9c55e41c73af5c4511070933b1bd25248521270c","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"3a30f6469b058574f49efde61cd6f5d79e576053","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"a01aee7cafc575bb82f5529e8734e7052f9b16ea","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bridge/br_arp_nd_proxy.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.15","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/bridge/br_arp_nd_proxy.c"]}],"references":["https://git.kernel.org/stable/c/c68433fd291c9e88c00292095172c62d1997d662","https://git.kernel.org/stable/c/4f397b950c916e9a1f8a4fce04ea0110206cad47","https://git.kernel.org/stable/c/bd91ec85aa4c77d645bd2739fc56784157a88ca2","https://git.kernel.org/stable/c/658261898130da620fc3d0fbb0523efb3366cb55","https://git.kernel.org/stable/c/2ba4caba423ed94d63006eb1d2227b0332ab7fcd","https://git.kernel.org/stable/c/9c55e41c73af5c4511070933b1bd25248521270c","https://git.kernel.org/stable/c/3a30f6469b058574f49efde61cd6f5d79e576053","https://git.kernel.org/stable/c/a01aee7cafc575bb82f5529e8734e7052f9b16ea","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":["CWE-125"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31682.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31682","state":"PUBLISHED","datePublished":"2026-04-25T08:46:59.106Z","dateUpdated":"2026-10-19T18:56:04.675Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.130Z"},"containers":{"cna":{"title":"bridge: br_nd_send: linearize skb before parsing ND options","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: br_nd_send: linearize skb before parsing ND options\n\nbr_nd_send() parses neighbour discovery options from ns->opt[] and\nassumes that these options are in the linear part of request.\n\nIts callers only guarantee that the ICMPv6 header and target address\nare available, so the option area can still be non-linear. Parsing\nns->opt[] in that case can access data past the linear buffer.\n\nLinearize request before option parsing and derive ns from the linear\nnetwork header."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"c68433fd291c9e88c00292095172c62d1997d662","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"4f397b950c916e9a1f8a4fce04ea0110206cad47","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"bd91ec85aa4c77d645bd2739fc56784157a88ca2","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"658261898130da620fc3d0fbb0523efb3366cb55","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"2ba4caba423ed94d63006eb1d2227b0332ab7fcd","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"9c55e41c73af5c4511070933b1bd25248521270c","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"3a30f6469b058574f49efde61cd6f5d79e576053","versionType":"git"},{"version":"ed842faeb2bd49256f00485402f3113205f91d30","status":"affected","lessThan":"a01aee7cafc575bb82f5529e8734e7052f9b16ea","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bridge/br_arp_nd_proxy.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.15","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/bridge/br_arp_nd_proxy.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c68433fd291c9e88c00292095172c62d1997d662"},{"url":"https://git.kernel.org/stable/c/4f397b950c916e9a1f8a4fce04ea0110206cad47"},{"url":"https://git.kernel.org/stable/c/bd91ec85aa4c77d645bd2739fc56784157a88ca2"},{"url":"https://git.kernel.org/stable/c/658261898130da620fc3d0fbb0523efb3366cb55"},{"url":"https://git.kernel.org/stable/c/2ba4caba423ed94d63006eb1d2227b0332ab7fcd"},{"url":"https://git.kernel.org/stable/c/9c55e41c73af5c4511070933b1bd25248521270c"},{"url":"https://git.kernel.org/stable/c/3a30f6469b058574f49efde61cd6f5d79e576053"},{"url":"https://git.kernel.org/stable/c/a01aee7cafc575bb82f5529e8734e7052f9b16ea"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable code is reached by received IPv6/ICMPv6 Neighbor Solicitation traffic on a Linux bridge port before any protocol authentication. In bridged physical or virtual deployments, a network peer can send the crafted packet to the affected bridge path.\nAC:L - There is no race, and the attacker controls the packet contents and can repeat attempts to hit a non-linear skb receive path. Neighbor suppression and a valid neighbor/FDB state are deployment prerequisites, but not per-attempt conditions outside a reasonable affected configuration.\nPR:N - The packet receive path has no credential or authentication check before `br_nd_send()` is reached. CAP_NET_ADMIN is needed to configure bridge neighbor suppression, but exploiting an already configured bridge requires no privileges.\nUI:N - No victim user action is required once the bridge is in the affected configuration. The attacker only needs to send crafted network traffic.\nS:U - The vulnerable component and impacted resources are the same kernel networking/bridge security authority. This is not a hypervisor, IOMMU, or separate security-scope escape by itself.\nC:H - The bug is an out-of-bounds read past the skb linear area while parsing attacker-controlled ND options. The read data can influence bytes copied into the generated Neighbor Advertisement, and under the required rule an OOB read that is not strictly bounded to a few bytes is High.\nI:N - The vulnerable operation reads memory past the linear skb buffer but does not write to kernel memory or provide a direct data-modification primitive. The generated reply may be misaddressed, but the bug does not give meaningful integrity modification.\nA:H - Reading past the linear buffer can trigger a kernel fault/oops or panic depending on skb layout and memory mapping. 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