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CVE-2026-80789

Estado: RecibidaSin puntuar—

In the Linux kernel, the following vulnerability has been resolved:

nvmet-tcp: bound SGL data length before allocating command buffers

nvmet_tcp_map_data() reads the host-controlled 32-bit sgl->length and, for the in-capsule offset descriptor (type 0x01), checks it against port->inline_data_size before use. Any other SGL descriptor type -- including the non-inline transport SGL data-block descriptor (type (NVME_TRANSPORT_SGL_DATA_DESC << 4) | NVME_SGL_FMT_TRANSPORT_A, the type a real host uses for out-of-capsule writes) skips that check entirely and falls straight through to:

with len taken directly from the wire, unbounded up to 4 GiB.

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nvmet_req_init() only parses the command and never inspects sgl->length, and nvmet_check_transfer_len() -- the only other place transfer_len is validated -- runs later, from req->execute(), after the allocation has already happened. For a write command the target responds with an R2T and parks the command waiting for the host to send the data; if the host (or an unauthenticated peer that simply never follows up) never does, the sgl_alloc() buffer stays resident for the life of the command. NVMe/TCP has no mandatory authentication in the default configuration, so any peer able to reach the target portal and complete a Fabrics connect can drive this with a single crafted command, repeatable across queues and connections for amplification. This is unbounded kernel memory allocation triggered by a remote, effectively unauthenticated peer.

Validate len against the same NVMET_TCP_MAXH2CDATA ceiling this file already uses to bound per-PDU H2C data, for every SGL descriptor type, before doing any allocation. This closes the gap for the non-inline descriptor while leaving the existing, tighter inline_data_size check in place for the in-capsule case.

Runtime-verified on a v6.19 KASAN stand: with this bound in place, a crafted write command carrying an oversized non-inline SGL length is rejected before sgl_alloc() runs, where the same request previously drove an unbounded ~256 MiB kernel allocation (up to 4 GiB) that stayed resident pending an R2T the host never satisfies.

Detalles técnicos trazas, registros y código del informe original
	cmd->req.sg = sgl_alloc(len, GFP_KERNEL, &cmd->req.sg_cnt);

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-80789",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
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          "product": "Linux",
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              "version": "0",
              "lessThan": "5.0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "5.10.269",
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              "status": "unaffected",
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              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/nvme/target/tcp.c"
          ],
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        }
      ]
    }
  ],
  "published": "2026-09-04T16:18:05.010",
  "references": [
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      "url": "https://git.kernel.org/stable/c/0952541b153e258b99d39cdb03ea6919fdeb41d0",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d895e66628f939edbb98608f6e033d3d39e6e546",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f6e51b09cbaa5f6f6e6a3a9dafa666f76c37aab5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "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->length\nand, for the in-capsule offset descriptor (type 0x01), checks it\nagainst port->inline_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 << 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->req.sg = sgl_alloc(len, GFP_KERNEL, &cmd->req.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->length, and nvmet_check_transfer_len() -- the only other place\ntransfer_len is validated -- runs later, from req->execute(), 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."
    }
  ],
  "lastModified": "2026-09-04T16:18:05.010",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}