Vulnerability-Lookup

CVE-2026-64263 (GCVE-0-2026-64263)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-07-25 08:49

Title

fuse-uring: fix moving cancelled entry to ent_in_userspace list

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.

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/50f3e03db823cabc4…
https://git.kernel.org/stable/c/e8afc85acdf329361…
https://git.kernel.org/stable/c/198f45eeb9f78b2a2…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 4fea593e625cd50d4d11be227007849b12f17bfb , < 50f3e03db823cabc41fe35c27d77c2bdb112baad (git) Affected: 4fea593e625cd50d4d11be227007849b12f17bfb , < e8afc85acdf329361b2d8df2ad9b52364686235f (git) Affected: 4fea593e625cd50d4d11be227007849b12f17bfb , < 198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

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          "versions": [
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            },
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            },
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          "url": "https://git.kernel.org/stable/c/198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc"
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    "datePublished": "2026-07-25T08:49:13.217Z",
    "dateReserved": "2026-07-19T15:36:31.774Z",
    "dateUpdated": "2026-07-25T08:49:13.217Z",
    "state": "PUBLISHED"
  },
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    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-07-25T16:47:03Z",
      "cve": "CVE-2026-64263",
      "id": "CVE-2026-64263",
      "initial_release_date": "2026-07-25T16:47:03Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64263",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64263.json",
      "version": "2"
    }
  }
}

GHSA-298C-3CXP-3C2H

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

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.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64263"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:06Z",
    "severity": null
  },
  "details": "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": "GHSA-298c-3cxp-3c2h",
  "modified": "2026-07-25T12:31:28Z",
  "published": "2026-07-25T12:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64263"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/198f45eeb9f78b2a2d6d8be95e4e43468eb2c6bc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/50f3e03db823cabc41fe35c27d77c2bdb112baad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e8afc85acdf329361b2d8df2ad9b52364686235f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-64263 (GCVE-0-2026-64263)

GHSA-298C-3CXP-3C2H

Tags

Sightings

Nomenclature