CVE-2026-74481: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hf76-hfqm-mx9q",
  "modified" : "2026-08-19T18:32:28Z",
  "published" : "2026-08-15T15:30:34Z",
  "aliases" : [ "CVE-2026-74481" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_reporting: use system_freezable_wq to fix UAF during suspend\n\nDuring PM freeze (e.g.  S3 suspend or S4 hibernation), device drivers like\nvirtio_balloon reset their underlying virtio devices and delete their\nvirtqueues via vdev->config->del_vqs().\n\nHowever, page reporting work (page_reporting_process) was scheduled on the\nglobal system_wq.  Because system_wq lacks the WQ_FREEZABLE flag, the PM\nfreezer skips it, leaving page_reporting_process active during suspend.\n\nIf pages are freed into the buddy allocator while suspending (for example,\nwhen core MM invokes the balloon shrinker during S4 hibernation image\nsaving), page reporting triggers virtballoon_free_page_report() on deleted\nvirtqueues, resulting in a Use-After-Free / General Protection Fault:\n\n    [  196.795226] general protection fault, probably for non-canonical address 0xaa1436fe70dae6df: 0000 [#1] SMP NOPTI\n    [  196.825967] Workqueue: events page_reporting_process\n    [  196.831038] RIP: 0010:virtqueue_add_split+0x233/0x4c0 [virtio_ring]\n    [  196.927073] virtballoon_free_page_report+0x3a/0xe0 [virtio_balloon]\n    [  196.946943] page_reporting_process+0x370/0x4f0\n\nFix this by switching page reporting work to system_freezable_wq.  This\nensures that the PM freezer pauses page_reporting_process before device\ndrivers destroy their reporting virtqueues.  Because the reporting worker\nis frozen, memory reclamation/freeing (e.g.  via shrinker execution) can\nsafely return pages to MM during freeze without triggering unfrozen\nreporting work on deleted virtqueues.\n\nThis aligns with the driver's existing design. The comment in\nvirtballoon_freeze() states:\n    /*\n     * The workqueue is already frozen by the PM core before this\n     * function is called.\n     */\n\nTesting:\nI have verified these fixes using Google’s virtualization infrastructure\nby running continuous suspend/resume iterations (40+ cycles) while\nchurning memory using stress-ng (`stress-ng --vm 4 --vm-bytes 60%\n--timeout 1`) to constantly create free pages for the buddy allocator.  We\nalso set the `page_reporting_order` parameter to 0 to make the page\nreporting worker highly sensitive, forcing it to pick up any 4K free\npages.  This confirmed that the UAF crashes are no longer reproducible.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-74481"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/0b45f6927a14914ff685fe0e6f9d11232a1e03df"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/450f35f4d5a682a0796757e52295df58ddb63bc9"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/992f270fd808338fbae1f498a5e325e7e2e20368"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/a4c60046052777ca1dcc83fe3ece2a5136b301f1"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b11907c905fa08eda925395f0724b7a409870f65"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b2c094e98f8bb823b3ae475f7169fe2091c40c6d"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/f978048326570047e8216e81a67f9c71ef2bb1b1"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/faf439b5fa7b231120eac4f7a617e0bfd4f6f5c7"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-15T13:17:52Z"
  }
}