CVE-2026-64259 (GCVE-0-2026-64259)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:49 – Updated: 2026-08-17 04:52
VLAI
Title
fuse-uring: make a fuse_req on SQE commit only findable after memcpy
Summary
In the Linux kernel, the following vulnerability has been resolved: fuse-uring: make a fuse_req on SQE commit only findable after memcpy Bad userspace might try to trick us and send commit SQEs request unique / commit-id of requests that are not even send to fuse-server (io_uring_cmd_done() not called) yet. fuse_uring_commit_fetch() ends the fuse request when the ring entry has a wrong state, but that could have caused a use-after-free with the memcpy operations in fuse_uring_send_in_task(). In order to avoid such races the call of fuse_uring_add_to_pq() is moved after the copy operations and just before completing the io-uring request - malicious userspace cannot find the request anymore until all prepration work in fuse-client/kernel is completed. This also moves fuse_uring_add_to_pq() a bit up in the code to avoid a forward declaration. Also not with a preparation commit, to make it easier to back port to older kernels.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c090c8abae4b6b77a1bee116aa6c385456ebef96 , < e1711479e9068ea31b31353a702a51e639c3d059 (git)
Affected: c090c8abae4b6b77a1bee116aa6c385456ebef96 , < a635f427d57e2012102ae4886b48d8955c59fb86 (git)
Affected: c090c8abae4b6b77a1bee116aa6c385456ebef96 , < 1efd3d474fc0ba74dfd984249bca78807d739812 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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      "cve": "CVE-2026-64259",
      "id": "CVE-2026-64259",
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      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: fuse-uring: make a fuse_req on SQE commit only findable after memcpy",
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}



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