{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.19.12-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "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.",
  "id": "DEBIAN-CVE-2026-31769",
  "modified": "2026-09-14T16:47:38.713465821Z",
  "published": "2026-05-01T15:16:40.090Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-31769"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-31769"
  ]
}