{"id":"AZL-99539","summary":"CVE-2026-80789 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: bound SGL data length before allocating command buffers\n\nnvmet_tcp_map_data() reads the host-controlled 32-bit sgl-\u003elength\nand, for the in-capsule offset descriptor (type 0x01), checks it\nagainst port-\u003einline_data_size before use. Any other SGL descriptor\ntype -- including the non-inline transport SGL data-block descriptor\n(type (NVME_TRANSPORT_SGL_DATA_DESC \u003c\u003c 4) | NVME_SGL_FMT_TRANSPORT_A,\nthe type a real host uses for out-of-capsule writes) skips that check\nentirely and falls straight through to:\n\n\tcmd-\u003ereq.sg = sgl_alloc(len, GFP_KERNEL, &cmd-\u003ereq.sg_cnt);\n\nwith len taken directly from the wire, unbounded up to 4 GiB.\n\nnvmet_req_init() only parses the command and never inspects\nsgl-\u003elength, and nvmet_check_transfer_len() -- the only other place\ntransfer_len is validated -- runs later, from req-\u003eexecute(), after\nthe allocation has already happened. For a write command the target\nresponds with an R2T and parks the command waiting for the host to\nsend the data; if the host (or an unauthenticated peer that simply\nnever follows up) never does, the sgl_alloc() buffer stays resident\nfor the life of the command. NVMe/TCP has no mandatory authentication\nin the default configuration, so any peer able to reach the target\nportal and complete a Fabrics connect can drive this with a single\ncrafted command, repeatable across queues and connections for\namplification. This is unbounded kernel memory allocation\ntriggered by a remote, effectively unauthenticated peer.\n\nValidate len against the same NVMET_TCP_MAXH2CDATA ceiling this file\nalready uses to bound per-PDU H2C data, for every SGL descriptor type,\nbefore doing any allocation. This closes the gap for the non-inline\ndescriptor while leaving the existing, tighter inline_data_size check\nin place for the in-capsule case.\n\nRuntime-verified on a v6.19 KASAN stand: with this bound in place, a\ncrafted write command carrying an oversized non-inline SGL length is\nrejected before sgl_alloc() runs, where the same request previously\ndrove an unbounded ~256 MiB kernel allocation (up to 4 GiB) that\nstayed resident pending an R2T the host never satisfies.","modified":"2026-09-05T14:16:51.759627240Z","published":"2026-09-04T16:18:05Z","upstream":["CVE-2026-80789"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80789"}],"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-99539.json"}}],"schema_version":"1.9.0"}