GHSA-PXX7-9R2R-M5M2

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31
VLAI
Details

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

fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions

The BPF verifier and the dynptr abstraction ensure that the memory space referenced by a dynptr remains valid. They do not, however, provide any guarantee that the contents of the memory are stable. kfuncs are expected to remain memory-safe even if concurrent modifications occur.

bpf_get_fsverity_digest() didn't follow that: it could crash if arg->digest_size was concurrently modified.

Fix that by using the known-good value hash_alg->digest_size instead.

Also widen 'dynptr_sz' and 'out_digest_sz' to u64 to match the return type of __bpf_dynptr_size(). It doesn't appear that it can actually be more than INT_MAX currently (since __bpf_dynptr_data_rw() excludes file-based pointers), but the correct type might as well be used.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-74590"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:31Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfsverity: Fix bpf_get_fsverity_digest() dynptr assumptions\n\nThe BPF verifier and the dynptr abstraction ensure that the memory space\nreferenced by a dynptr remains valid.  They do not, however, provide any\nguarantee that the contents of the memory are stable.  kfuncs are\nexpected to remain memory-safe even if concurrent modifications occur.\n\nbpf_get_fsverity_digest() didn\u0027t follow that: it could crash if\narg-\u003edigest_size was concurrently modified.\n\nFix that by using the known-good value hash_alg-\u003edigest_size instead.\n\nAlso widen \u0027dynptr_sz\u0027 and \u0027out_digest_sz\u0027 to u64 to match the return\ntype of __bpf_dynptr_size().  It doesn\u0027t appear that it can actually be\nmore than INT_MAX currently (since __bpf_dynptr_data_rw() excludes\nfile-based pointers), but the correct type might as well be used.",
  "id": "GHSA-pxx7-9r2r-m5m2",
  "modified": "2026-08-25T06:31:21Z",
  "published": "2026-08-22T18:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74590"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1344b632cb5043e32939a84568125719111c5af3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2a5cfcad1d56e26d645b7887b0ed24c371851525"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e8ec7c0387273329374f5c7bd61f5f38af71fe1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5bd63cad9df4328a184c409fbdad4f17944bcdb8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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