{
  "cveId": "CVE-2026-31769",
  "url": "https://patchblox.com/security/cve/CVE-2026-31769",
  "summary": "CVE-2026-31769 is fixed in linux on 1 platform by DEBIAN-CVE-2026-31769 (version 6.19.12-1), released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "gpib: fix use-after-free in IO ioctl handlers",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  gpib: fix use-after-free in IO ioctl handlers  The IBRD, IBWRT, IBCMD, and IBWAIT ioctl handlers use a gpib_descriptor pointer after board-\u003Ebig_gpib_mutex has been released.  A concurrent IBCLOSEDEV ioctl can free the descriptor via close_dev_ioctl() during this window, causing a use-after-free.  The IO handlers (read_ioctl, write_ioctl, command_ioctl) explicitly release big_gpib_mutex before calling their handler.  wait_ioctl() is called with big_gpib_mutex held, but ibwait() releases it internally when wait_mask is non-zero.  In all four cases, the descriptor pointer obtained from handle_to_descriptor() becomes unprotected.  Fix this by introducing a kernel-only descriptor_busy reference count in struct gpib_descriptor.  Each handler atomically increments descriptor_busy under file_priv-\u003Edescriptors_mutex before releasing the lock, and decrements it when done.  close_dev_ioctl() checks descriptor_busy under the same lock and rejects the close with -EBUSY if the count is non-zero.  A reference count rather than a simple flag is necessary because multiple handlers can operate on the same descriptor concurrently (e.g. IBRD and IBWAIT on the same handle from different threads).  A separate counter is needed because io_in_progress can be cleared from unprivileged userspace via the IBWAIT ioctl (through general_ibstatus() with set_mask containing CMPL), which would allow an attacker to bypass a check based solely on io_in_progress.  The new descriptor_busy counter is only modified by the kernel IO paths.  The lock ordering is consistent (big_gpib_mutex -\u003E descriptors_mutex) and the handlers only hold descriptors_mutex briefly during the lookup, so there is no deadlock risk and no impact on IO throughput.",
  "published": "2026-05-01T15:16:40Z",
  "severity": "high",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00131,
  "epssPercentile": 0.02742,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31769",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.19.12-1",
      "fix": "DEBIAN-CVE-2026-31769",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-31769",
      "released": "2026-05-15T16:01:09Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}