FKIE_CVE-2026-43442

Vulnerability from fkie_nvd - Published: 2026-05-08 15:16 - Updated: 2026-05-21 17:10
Severity
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops When IORING_SETUP_SQE_MIXED is used without IORING_SETUP_NO_SQARRAY, the boundary check for 128-byte SQE operations in io_init_req() validated the logical SQ head position rather than the physical SQE index. The existing check: !(ctx->cached_sq_head & (ctx->sq_entries - 1)) ensures the logical position isn't at the end of the ring, which is correct for NO_SQARRAY rings where physical == logical. However, when sq_array is present, an unprivileged user can remap any logical position to an arbitrary physical index via sq_array. Setting sq_array[N] = sq_entries - 1 places a 128-byte operation at the last physical SQE slot, causing the 128-byte memcpy in io_uring_cmd_sqe_copy() to read 64 bytes past the end of the SQE array. Replace the cached_sq_head alignment check with a direct validation of the physical SQE index, which correctly handles both sq_array and NO_SQARRAY cases.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1f794f9bed3e5cf7250a3b4daf112a72ed1513e9Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6f02c6b196036dbb6defb4647d8707d29b7fe95bPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
To clipboard 

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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops\n\nWhen IORING_SETUP_SQE_MIXED is used without IORING_SETUP_NO_SQARRAY,\nthe boundary check for 128-byte SQE operations in io_init_req()\nvalidated the logical SQ head position rather than the physical SQE\nindex.\n\nThe existing check:\n\n  !(ctx-\u003ecached_sq_head \u0026 (ctx-\u003esq_entries - 1))\n\nensures the logical position isn\u0027t at the end of the ring, which is\ncorrect for NO_SQARRAY rings where physical == logical. However, when\nsq_array is present, an unprivileged user can remap any logical\nposition to an arbitrary physical index via sq_array. Setting\nsq_array[N] = sq_entries - 1 places a 128-byte operation at the last\nphysical SQE slot, causing the 128-byte memcpy in\nio_uring_cmd_sqe_copy() to read 64 bytes past the end of the SQE\narray.\n\nReplace the cached_sq_head alignment check with a direct validation\nof the physical SQE index, which correctly handles both sq_array and\nNO_SQARRAY cases."
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  "id": "CVE-2026-43442",
  "lastModified": "2026-05-21T17:10:51.703",
  "metrics": {
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
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        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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  "published": "2026-05-08T15:16:56.663",
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