{
  "cveId": "CVE-2026-90193",
  "url": "https://patchblox.com/security/cve/CVE-2026-90193",
  "summary": "CVE-2026-90193 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-90193, released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  mailbox: qcom-cpucp: fix PREEMPT_RT self-deadlock in IRQ handler  qcom_cpucp_mbox_irq_fn() calls mbox_chan_received_data() while holding chan-\u003Elock. Under PREEMPT_RT, spin_lock_irqsave() is converted to an rt_spinlock (rtmutex-based), which tracks ownership and can sleep.  The callback chain triggered by mbox_chan_received_data() eventually reaches mailbox_clear_channel() -\u003E mbox_send_message() -\u003E add_to_rbuf(), which attempts to re-acquire the same chan-\u003Elock. Since rtmutex detects the re-entrant lock attempt by the same owner, the thread blocks waiting for a lock it already holds, causing a permanent deadlock.  This deadlock manifests as \u0027irq/N-apss_cpucp_mbox\u0027 stuck in D state with the following call trace:   rt_spin_lock -\u003E mbox_send_message -\u003E mailbox_clear_channel -\u003E   scmi_rx_callback -\u003E mbox_chan_received_data [\u003C- held chan-\u003Elock here]  Fix by saving chan-\u003Ecl locally and clearing the HW interrupt register inside the lock, then invoking mbox_chan_received_data() after releasing the lock. This preserves the mutual exclusion for chan-\u003Ecl access while avoiding the lock re-entrancy that causes the PREEMPT_RT deadlock.",
  "published": "2026-09-17T17:17:14Z",
  "severity": "",
  "epss": 0.00209,
  "epssPercentile": 0.11095,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-90193",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.111-1",
      "fix": "DEBIAN-CVE-2026-90193",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-90193",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-90193",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-90193",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.111-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-90193",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-90193",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}