CVE-2026-68095 (GCVE-0-2026-68095)
Vulnerability from cvelistv5
Published
2026-08-10 11:58
Modified
2026-08-17 04:58
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix race between registration and connection abortion This fixes this race: - thread a: io_uring_enter -> register sqe -> fuse_uring_create_ring_ent -> allocate ent but doesn't grab queue_ref yet - thread b: fuse_conn_destroy() -> fuse_chan_abort() -> fuse_uring_abort() is a no-op due to queue ref being 0 - thread a: grabs the queue_ref, queue_ref is now 1, rest of fuse_uring_do_register() logic executes - thread b: fuse_chan_abort() returns, fuse_chan_wait_aborted() now runs and calls "wait_event(ring->stop_waitq, atomic_read(&ring->queue_refs) == 0);" The abort/unmount thread will hang indefinitely in unkillable state as nothing will decrement queue_refs or wake stop_waitq, and the ring, queue, and ent are leaked. Fix this by checking fch->connected under fch->lock after the created ent has grabbed a ref count on the queue. This ensures that in the scenario above, it is guaranteed that we either release the queue ref and wake up stop_waitq (in case fuse_chan_wait_aborted() is already waiting) in fuse_uring_do_register() when we detect !fch->connected, or if the connection is aborted after the check, it is guaranteed that the async teardown worker will be running in the background cleaning up ents and decrementing the ent's ref on the queue, which will unblock the eventual queue and ring teardown.
References
Impacted products
Vendor Product Version
Linux Linux Version: 24fe962c86f55347385933a1b06ca71b60854690
Version: 24fe962c86f55347385933a1b06ca71b60854690
Version: 24fe962c86f55347385933a1b06ca71b60854690
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/dev_uring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3bca70235a706de76fe9a81defd37d987062c686",
              "status": "affected",
              "version": "24fe962c86f55347385933a1b06ca71b60854690",
              "versionType": "git"
            },
            {
              "lessThan": "2cd945492bc5b472e814272e88b731bb9bb17629",
              "status": "affected",
              "version": "24fe962c86f55347385933a1b06ca71b60854690",
              "versionType": "git"
            },
            {
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/dev_uring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix race between registration and connection abortion\n\nThis fixes this race:\n- thread a: io_uring_enter -\u003e register sqe -\u003e\n  fuse_uring_create_ring_ent -\u003e allocate ent but doesn\u0027t grab queue_ref\n  yet\n- thread b: fuse_conn_destroy() -\u003e fuse_chan_abort() -\u003e\n  fuse_uring_abort() is a no-op due to queue ref being 0\n- thread a: grabs the queue_ref, queue_ref is now 1, rest of\n  fuse_uring_do_register() logic executes\n- thread b: fuse_chan_abort() returns, fuse_chan_wait_aborted() now runs\n  and calls\n  \"wait_event(ring-\u003estop_waitq, atomic_read(\u0026ring-\u003equeue_refs) == 0);\"\nThe abort/unmount thread will hang indefinitely in unkillable state as\nnothing will decrement queue_refs or wake stop_waitq, and the ring,\nqueue, and ent are leaked.\n\nFix this by checking fch-\u003econnected under fch-\u003elock after the created\nent has grabbed a ref count on the queue. This ensures that in the\nscenario above, it is guaranteed that we either release the queue ref\nand wake up stop_waitq (in case fuse_chan_wait_aborted() is already\nwaiting) in fuse_uring_do_register() when we detect !fch-\u003econnected, or\nif the connection is aborted after the check, it is guaranteed that the\nasync teardown worker will be running in the background cleaning up ents\nand decrementing the ent\u0027s ref on the queue, which will unblock the\neventual queue and ring teardown."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:58:43.670Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3bca70235a706de76fe9a81defd37d987062c686"
        },
        {
          "url": "https://git.kernel.org/stable/c/2cd945492bc5b472e814272e88b731bb9bb17629"
        },
        {
          "url": "https://git.kernel.org/stable/c/952b5d36f6a298f57c52a59e72076c69386a8aaf"
        }
      ],
      "title": "fuse-uring: fix race between registration and connection abortion",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68095",
    "datePublished": "2026-08-10T11:58:08.590Z",
    "dateReserved": "2026-07-30T09:28:09.367Z",
    "dateUpdated": "2026-08-17T04:58:43.670Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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