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CVE-2026-90095

Estado: RecibidaSin puntuar—

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

fuse: Fix the condition to enable over-io-uring

The existing condition in fuse_uring_cmd() is there only to avoid disabling io-uring for connections that already run with it, missing was a condition to refuse any IORING_OP_URING_CMD if the connection/channel didn't get enabled because of missing FUSE_INIT reply flag FUSE_OVER_IO_URING. Without the reply flag the barrier in fuse_uring_ready() doesn't work and IO could already be going on and cause deadlock states (at a minimum one between fch->bg_lock and queue->lock).

The change itself is trivial, but brings behavior change, FUSE_OVER_IO_URING has to be set in the FUSE_INIT_REPLY by fuse servers to accept any IORING_OP_URING_CMD.

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Libfuse does that and the only non-libfuse implementation I found (fractal-fuse) also does it. Qemu patches for fuse-io-uring are not merged yet, as far as I know.

Moved up is the smp_load_acquire(&fch->initialized) check, as a fuse-server implementation might try to setup io-uring before FUSE_INIT is processed and might have gotten -EOPNOTSUPP instead of -EAGAIN.

Also fixed is a stale comment that explains the handling of the FUSE_OVER_IO_URING flag in early RFC versions.

If there should be a report from any library or application we probably need to revert this commit.

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.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-90095",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3393ff964e0fa5def66570c54a4612bf9df06b76",
              "lessThan": "8f9a725d89711ad027f6b7183586ef91528f106d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3393ff964e0fa5def66570c54a4612bf9df06b76",
              "lessThan": "1f59015e958174e89be58cc8db16d70a60d17255",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/fuse/dev_uring.c",
            "fs/fuse/inode.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.14",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/fuse/dev_uring.c",
            "fs/fuse/inode.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:17:01.123",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1f59015e958174e89be58cc8db16d70a60d17255",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8f9a725d89711ad027f6b7183586ef91528f106d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: Fix the condition to enable over-io-uring\n\nThe existing condition in fuse_uring_cmd() is there only to avoid\ndisabling io-uring for connections that already run with it, missing\nwas a condition to refuse any IORING_OP_URING_CMD if the\nconnection/channel didn't get enabled because of missing FUSE_INIT\nreply flag FUSE_OVER_IO_URING. Without the reply flag the barrier in\nfuse_uring_ready() doesn't work and IO could already be going on and\ncause deadlock states (at a minimum one between fch->bg_lock and\nqueue->lock).\n\nThe change itself is trivial, but brings behavior change,\nFUSE_OVER_IO_URING has to be set in the FUSE_INIT_REPLY by fuse servers\nto accept any IORING_OP_URING_CMD. Libfuse does that and the only\nnon-libfuse implementation I found (fractal-fuse) also does it.\nQemu patches for fuse-io-uring are not merged yet, as far as I know.\n\nMoved up is the smp_load_acquire(&fch->initialized) check, as a\nfuse-server implementation might try to setup io-uring before FUSE_INIT\nis processed and might have gotten -EOPNOTSUPP instead of -EAGAIN.\n\nAlso fixed is a stale comment that explains the handling of the\nFUSE_OVER_IO_URING flag in early RFC versions.\n\nIf there should be a report from any library or application we\nprobably need to revert this commit."
    }
  ],
  "lastModified": "2026-09-17T17:17:01.123",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}