GHSA-RW5P-XFF5-86QJ

Vulnerability from github – Published: 2026-08-12 00:31 – Updated: 2026-08-12 00:31
VLAI
Details

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

drm/vc4: Prevent shader BO mappings from becoming writable

vc4_gem_object_mmap() rejects a writable mapping of a validated shader BO, but leaves VM_MAYWRITE set. Userspace can map the BO read-only and then turn it writable with mprotect().

Validated shader BOs must stay read-only: the validator checks the instructions once and the GPU trusts them afterwards. A writable mapping lets userspace rewrite the code after validation, bypassing the validator.

Clear VM_MAYWRITE on the read-only path so the mapping cannot be upgraded, as i915 already does for its read-only objects.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68445"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-12T00:17:44Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/vc4: Prevent shader BO mappings from becoming writable\n\nvc4_gem_object_mmap() rejects a writable mapping of a validated shader\nBO, but leaves VM_MAYWRITE set.  Userspace can map the BO read-only and\nthen turn it writable with mprotect().\n\nValidated shader BOs must stay read-only: the validator checks the\ninstructions once and the GPU trusts them afterwards.  A writable\nmapping lets userspace rewrite the code after validation, bypassing the\nvalidator.\n\nClear VM_MAYWRITE on the read-only path so the mapping cannot be\nupgraded, as i915 already does for its read-only objects.",
  "id": "GHSA-rw5p-xff5-86qj",
  "modified": "2026-08-12T00:31:13Z",
  "published": "2026-08-12T00:31:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68445"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/019e6ad247f7fd038d2e009789f6d9bfcccb1ae7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c9e6367639548307d3f578f6943ce72c9d39087"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6deaa317201851c644c431b57682e54d06b35838"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f0ee411fc2d76333d6087c5862ffa907cf7a175"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fe168ef1d232d734d9998fd74822e2e20930dfff"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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