CVE-2026-98858 (GCVE-0-2026-98858)
Vulnerability from cvelistv5
Published
2026-10-18 15:51
Modified
2026-10-19 09:26
Severity ?
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: af5d68f8892f8ee8f137648b79ceb2abc153a19b
Version: af5d68f8892f8ee8f137648b79ceb2abc153a19b
Version: af5d68f8892f8ee8f137648b79ceb2abc153a19b
Version: af5d68f8892f8ee8f137648b79ceb2abc153a19b
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{
  "containers": {
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        {
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          "product": "Linux",
          "programFiles": [
            "io_uring/io_uring.c",
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      "cpeApplicability": [
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              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:26:52.852Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/42b3332efacfd2140be4cd0dedad4fb96b8ae90e"
        },
        {
          "url": "https://git.kernel.org/stable/c/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c"
        },
        {
          "url": "https://git.kernel.org/stable/c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3"
        },
        {
          "url": "https://git.kernel.org/stable/c/a92193c91e8839fe5fc209616ea95465ae4b919d"
        }
      ],
      "title": "io_uring: fix task_work add use-after-free with SQPOLL",
      "x_generator": {
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      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "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"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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