{"id":"AZL-88935","summary":"CVE-2026-46130 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm-verity-fec: fix reading parity bytes split across blocks (take 3)\n\nfec_decode_bufs() assumes that the parity bytes of the first RS codeword\nit decodes are never split across parity blocks.\n\nThis assumption is false.  Consider v-\u003efec-\u003eblock_size == 4096 &&\nv-\u003efec-\u003eroots == 17 && fio-\u003enbufs == 1, for example.  In that case, each\ncall to fec_decode_bufs() consumes v-\u003efec-\u003eroots * (fio-\u003enbufs \u003c\u003c\nDM_VERITY_FEC_BUF_RS_BITS) = 272 parity bytes.\n\nConsidering that the parity data for each message block starts on a\nblock boundary, the byte alignment in the parity data will iterate\nthrough 272*i mod 4096 until the 3 parity blocks have been consumed.  On\nthe 16th call (i=15), the alignment will be 4080 bytes into the first\nblock.  Only 16 bytes remain in that block, but 17 parity bytes will be\nneeded.  The code reads out-of-bounds from the parity block buffer.\n\nFortunately this doesn't normally happen, since it can occur only for\ncertain non-default values of fec_roots *and* when the maximum number of\nbuffers couldn't be allocated due to low memory.  For example with\nblock_size=4096 only the following cases are affected:\n\n    fec_roots=17: nbufs in [1, 3, 5, 15]\n    fec_roots=19: nbufs in [1, 229]\n    fec_roots=21: nbufs in [1, 3, 5, 13, 15, 39, 65, 195]\n    fec_roots=23: nbufs in [1, 89]\n\nRegardless, fix it by refactoring how the parity blocks are read.","modified":"2026-08-31T05:26:27Z","published":"2026-05-28T10:16:28Z","upstream":["CVE-2026-46130"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46130"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-88935.json"}}],"schema_version":"1.9.0"}