CVE-2026-98858 (GCVE-0-2026-98858)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:51 – Updated: 2026-10-19 09:26
VLAI
Title
io_uring: fix task_work add use-after-free with SQPOLL
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring: fix task_work add use-after-free with SQPOLL For SQPOLL, the sqpoll thread runs task_work off its own list and doesn't need to be told about it, so it can pop and complete a request as soon as mpscq_push() has published it. If that was the last request holding the ring alive, io_ring_exit_work() then frees the ctx, stops the thread, and with it the tctx, while io_req_normal_work_add() is still looking at both after the push: BUG: KASAN: slab-use-after-free in io_req_normal_work_add+0x439/0x510 Read of size 4 at addr ff11000000ca0000 by task repro/55 (...) BUG: KASAN: slab-use-after-free in queue_work_on+0x25/0x70 Write of size 8 at addr ff11000000c3bd00 by task repro/55 Hold an RCU read lock across the add, like io_req_local_work_add() already does, and have io_ring_exit_work() wait for a grace period for SQPOLL rings as well before freeing the ctx.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6639 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: af5d68f8892f8ee8f137648b79ceb2abc153a19b , < 42b3332efacfd2140be4cd0dedad4fb96b8ae90e (git)
Affected: af5d68f8892f8ee8f137648b79ceb2abc153a19b , < 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c (git)
Affected: af5d68f8892f8ee8f137648b79ceb2abc153a19b , < 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3 (git)
Affected: af5d68f8892f8ee8f137648b79ceb2abc153a19b , < a92193c91e8839fe5fc209616ea95465ae4b919d (git)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.12.113 , ≤ 6.12.* (semver)
Unaffected: 6.18.56 , ≤ 6.18.* (semver)
Unaffected: 7.2.10 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix task_work add use-after-free with SQPOLL\n\nFor SQPOLL, the sqpoll thread runs task_work off its own list and\ndoesn\u0027t need to be told about it, so it can pop and complete a request\nas soon as mpscq_push() has published it. If that was the last request\nholding the ring alive, io_ring_exit_work() then frees the ctx, stops\nthe thread, and with it the tctx, while io_req_normal_work_add() is\nstill looking at both after the push:\n\n  BUG: KASAN: slab-use-after-free in io_req_normal_work_add+0x439/0x510\n  Read of size 4 at addr ff11000000ca0000 by task repro/55\n  (...)\n  BUG: KASAN: slab-use-after-free in queue_work_on+0x25/0x70\n  Write of size 8 at addr ff11000000c3bd00 by task repro/55\n\nHold an RCU read lock across the add, like io_req_local_work_add() already\ndoes, and have io_ring_exit_work() wait for a grace period for SQPOLL rings\nas well before freeing the ctx."
        }
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    "cveId": "CVE-2026-98858",
    "datePublished": "2026-10-18T15:51:19.578Z",
    "dateReserved": "2026-09-25T10:25:14.376Z",
    "dateUpdated": "2026-10-19T09:26:52.852Z",
    "state": "PUBLISHED"
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      "cve": "CVE-2026-98858",
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      "product_status:under_investigation": "1",
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          }
        ],
        "id": "CVE-2026-98858",
        "lastModified": "2026-10-19T10:19:49.880",
        "metrics": {},
        "published": "2026-10-18T16:17:40.257",
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      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98858.json",
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    "suse_vex": {
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}



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