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GHSA-XWQ5-6XRG-83HR

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix stack slot index in nospec checks

check_stack_write_fixed_off() computes the byte slot for a fixed-offset stack write as -off - 1, and records each written byte in slot_type[] with (slot - i) % BPF_REG_SIZE.

The Spectre v4 sanitization pre-check uses slot_type[i] instead. For a 4-byte write at fp-8 after the lower half of fp-8 has been zeroed, the pre-check scans bytes 0..3 and sees STACK_ZERO while the actual write updates bytes 7..4. That can leave the second half-slot write without nospec_result even though the bytes being overwritten still require sanitization.

Use the same slot index in the sanitization pre-check that the write path uses when updating slot_type[].

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72428"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:16Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix stack slot index in nospec checks\n\ncheck_stack_write_fixed_off() computes the byte slot for a fixed-offset\nstack write as -off - 1, and records each written byte in slot_type[] with\n(slot - i) % BPF_REG_SIZE.\n\nThe Spectre v4 sanitization pre-check uses slot_type[i] instead. For a\n4-byte write at fp-8 after the lower half of fp-8 has been zeroed, the\npre-check scans bytes 0..3 and sees STACK_ZERO while the actual write updates\nbytes 7..4. That can leave the second half-slot write without nospec_result\neven though the bytes being overwritten still require sanitization.\n\nUse the same slot index in the sanitization pre-check that the write path uses\nwhen updating slot_type[].",
  "id": "GHSA-xwq5-6xrg-83hr",
  "modified": "2026-08-15T06:32:24Z",
  "published": "2026-08-15T06:32:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72428"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/475405593de2b796224c6297aece44f321195919"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68b41e68a62299f26cb16af422b5c7d1c69dafd9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a71eb8f730a91271cf47ce291e785b6b7e54622f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ca119656baa8f48a56e0c2f3ab63fdd33ca9e307"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d1d53aa30ab3b5ae89161c9cc840b3f7489ad386"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/db8f1dcf5950b91886b9df4270bc816370d292c1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e62268e695075a481a6c4feeb022c19cf57422a6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f1471aa76d74e0df3b2a90731ca0208f498c670b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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