{
  "cveId": "CVE-2021-46988",
  "url": "https://patchblox.com/security/cve/CVE-2021-46988",
  "summary": "CVE-2021-46988 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-46988, released February 28, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  userfaultfd: release page in error path to avoid...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  userfaultfd: release page in error path to avoid BUG_ON  Consider the following sequence of events:  1. Userspace issues a UFFD ioctl, which ends up calling into    shmem_mfill_atomic_pte(). We successfully account the blocks, we    shmem_alloc_page(), but then the copy_from_user() fails. We return    -ENOENT. We don\u0027t release the page we allocated. 2. Our caller detects this error code, tries the copy_from_user() after    dropping the mmap_lock, and retries, calling back into    shmem_mfill_atomic_pte(). 3. Meanwhile, let\u0027s say another process filled up the tmpfs being used. 4. So shmem_mfill_atomic_pte() fails to account blocks this time, and    immediately returns - without releasing the page.  This triggers a BUG_ON in our caller, which asserts that the page should always be consumed, unless -ENOENT is returned.  To fix this, detect if we have such a \u0022dangling\u0022 page when accounting fails, and if so, release it before returning.",
  "published": "2024-02-28T09:15:37Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.0024,
  "epssPercentile": 0.15151,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.10.38-1",
      "fix": "DEBIAN-CVE-2021-46988",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-46988",
      "released": "2024-02-28T09:15:37Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.10.38-1",
      "fix": "DEBIAN-CVE-2021-46988",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-46988",
      "released": "2024-02-28T09:15:37Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.10.38-1",
      "fix": "DEBIAN-CVE-2021-46988",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-46988",
      "released": "2024-02-28T09:15:37Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T13:31:49Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}