FKIE_CVE-2026-64263

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-30 15:00
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix moving cancelled entry to ent_in_userspace list fuse_uring_cancel() moves entries that are available (these have no reqs attached) to the ent_in_userspace list. ent_list_request_expired() checks the first entry on ent_in_userspace and dereferences ent->fuse_req unconditionally, which will crash on a cancelled entry that was moved to this list. Fix this by freeing the entry and dropping queue_refs directly in fuse_uring_cancel(). This is safe because cancel is the cancel handler itself - after io_uring_cmd_done(), no more cancels will be dispatched for this command, and teardown serializes with cancel via queue->lock. Since cancel now decrements queue_refs, fuse_uring_abort() must no longer gate fuse_uring_abort_end_requests() on queue_refs > 0, as cancelled entries may have already dropped queue_refs while requests are still queued. Remove the gate so abort always flushes requests and stops queues.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/50f3e03db823cabc41fe35c27d77c2bdb112baad
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e8afc85acdf329361b2d8df2ad9b52364686235f
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/dev_uring.c",
            "fs/fuse/dev_uring_i.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "50f3e03db823cabc41fe35c27d77c2bdb112baad",
              "status": "affected",
              "version": "4fea593e625cd50d4d11be227007849b12f17bfb",
              "versionType": "git"
            },
            {
              "lessThan": "e8afc85acdf329361b2d8df2ad9b52364686235f",
              "status": "affected",
              "version": "4fea593e625cd50d4d11be227007849b12f17bfb",
              "versionType": "git"
            },
            {
              "lessThan": "198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc",
              "status": "affected",
              "version": "4fea593e625cd50d4d11be227007849b12f17bfb",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/fuse/dev_uring.c",
            "fs/fuse/dev_uring_i.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix moving cancelled entry to ent_in_userspace list\n\nfuse_uring_cancel() moves entries that are available (these have no reqs\nattached) to the ent_in_userspace list. ent_list_request_expired()\nchecks the first entry on ent_in_userspace and dereferences\nent-\u003efuse_req unconditionally, which will crash on a cancelled entry\nthat was moved to this list.\n\nFix this by freeing the entry and dropping queue_refs directly in\nfuse_uring_cancel(). This is safe because cancel is the cancel handler\nitself - after io_uring_cmd_done(), no more cancels will be dispatched\nfor this command, and teardown serializes with cancel via queue-\u003elock.\n\nSince cancel now decrements queue_refs, fuse_uring_abort() must no\nlonger gate fuse_uring_abort_end_requests() on queue_refs \u003e 0, as\ncancelled entries may have already dropped queue_refs while requests are\nstill queued. Remove the gate so abort always flushes requests and stops\nqueues."
    }
  ],
  "id": "CVE-2026-64263",
  "lastModified": "2026-07-30T15:00:27.343",
  "metrics": {},
  "published": "2026-07-25T10:17:06.460",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/50f3e03db823cabc41fe35c27d77c2bdb112baad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e8afc85acdf329361b2d8df2ad9b52364686235f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}



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