{"id":"AZL-90491","summary":"CVE-2026-53263 affecting package kernel for versions less than 6.6.143.1-1","details":"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-\u003es6_addr[11] as source, but\nboth should be offset by one: &data[2] and &ipaddr-\u003es6_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.","modified":"2026-08-28T17:47:35.526126465Z","published":"2026-06-25T09:16:44Z","upstream":["CVE-2026-53263"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53263"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.143.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-90491.json"}}],"schema_version":"1.9.0"}