{"id":"CVE-2026-53263","state":"PUBLISHED","title":"6lowpan: fix off-by-one in multicast context address compression","description":"In the Linux kernel, the following vulnerability has been resolved:\n\n6lowpan: fix off-by-one in multicast context address compression\n\nThe second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses\n&data[1] as destination and &ipaddr->s6_addr[11] as source, but\nboth should be offset by one: &data[2] and &ipaddr->s6_addr[12]\nrespectively.\n\nThis off-by-one has two consequences:\n1. data[1] is overwritten with s6_addr[11], corrupting the RIID\n   field in the compressed multicast address\n2. data[5] is never written, so uninitialized kernel stack memory\n   is transmitted over the network via lowpan_push_hc_data(),\n   leaking kernel stack contents\n\nThe correct inline data layout must match what the decompression\nfunction lowpan_uncompress_multicast_ctx_daddr() expects:\n  data[0..1] = s6_addr[1..2]  (flags/scope + RIID)\n  data[2..5] = s6_addr[12..15] (group ID)\n\nAlso zero-initialize the data array as a defensive measure against\nsimilar bugs in the future.","publishedAt":"2026-06-25T08:39:51.215Z","updatedAt":"2026-10-15T01:23:05.071Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"f24a58c72a45f4c109f3557a760cc4b60b7a6037","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"da8cbb64b47e9066b40af0de170901caf17b768c","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"4485d79617520d84ba5a14515e2b5136007d6deb","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"06ce6fc106b16dec9b535950db626261be865e5b","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"c32f30ef5e66adbfa102348e2e8a23776eb007cb","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"da8808463882c3f3c357b072e25053c2121f1419","versionType":"git"},{"version":"5609c185f24dffca5f6a9c127106869da150be03","status":"affected","lessThan":"2a58899d11009bffc7b4b32a571858f381121837","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/6lowpan/iphc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/6lowpan/iphc.c"]}],"references":["https://git.kernel.org/stable/c/f24a58c72a45f4c109f3557a760cc4b60b7a6037","https://git.kernel.org/stable/c/da8cbb64b47e9066b40af0de170901caf17b768c","https://git.kernel.org/stable/c/4485d79617520d84ba5a14515e2b5136007d6deb","https://git.kernel.org/stable/c/06ce6fc106b16dec9b535950db626261be865e5b","https://git.kernel.org/stable/c/dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af","https://git.kernel.org/stable/c/c32f30ef5e66adbfa102348e2e8a23776eb007cb","https://git.kernel.org/stable/c/da8808463882c3f3c357b072e25053c2121f1419","https://git.kernel.org/stable/c/2a58899d11009bffc7b4b32a571858f381121837","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53263.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53263","state":"PUBLISHED","datePublished":"2026-06-25T08:39:51.215Z","dateUpdated":"2026-10-15T01:23:05.071Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.394Z"},"containers":{"cna":{"title":"6lowpan: fix off-by-one in multicast context address compression","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\n6lowpan: fix off-by-one in multicast context address compression\n\nThe second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses\n&data[1] as destination and &ipaddr->s6_addr[11] as source, but\nboth should be offset by one: &data[2] and &ipaddr->s6_addr[12]\nrespectively.\n\nThis off-by-one has two consequences:\n1. data[1] is overwritten with s6_addr[11], corrupting the RIID\n   field in the compressed multicast address\n2. data[5] is never written, so uninitialized kernel stack memory\n   is transmitted over the network via lowpan_push_hc_data(),\n   leaking kernel stack contents\n\nThe correct inline data layout must match what the decompression\nfunction lowpan_uncompress_multicast_ctx_daddr() expects:\n  data[0..1] = s6_addr[1..2]  (flags/scope + RIID)\n  data[2..5] = s6_addr[12..15] (group ID)\n\nAlso zero-initialize the data array as a defensive measure against\nsimilar bugs in the 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