{
  "cveId": "CVE-2026-68438",
  "url": "https://patchblox.com/security/cve/CVE-2026-68438",
  "summary": "CVE-2026-68438 is fixed in linux on 1 platform by DEBIAN-CVE-2026-68438 (version 7.1.6-1), released August 13, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  smp: Make CSD lock acquisition atomic for debug...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  smp: Make CSD lock acquisition atomic for debug mode  Commit b0473dcd4b1d (\u0022smp: Improve smp_call_function_single() CSD-lock diagnostics\u0022) changed smp_call_function_single() so that, when CSD lock debugging is enabled, async !wait calls use the destination CPU csd_data. That improves diagnostics, but it also removes the single-writer property that made the old csd_lock() safe: multiple CPUs can now prepare the same destination CPU CSD concurrently.  csd_lock() currently waits for CSD_FLAG_LOCK to clear and then sets the bit with a non-atomic read-modify-write. Two senders can both see an unlocked CSD, set the bit, overwrite the callback fields, and enqueue the same llist node. Re-adding a node that is already the queue head can make node-\u003Enext point to itself, leaving the target CPU stuck walking call_single_queue. Later synchronous work, such as a TLB shootdown, can then remain queued and trigger soft-lockup warnings or panics.  Keep the single csd_lock() implementation, but when CSD lock debugging is enabled, acquire CSD_FLAG_LOCK with try_cmpxchg_acquire(). This makes the destination CPU CSD a real atomic lock in the only configuration where it can be shared by multiple remote senders, while preserving the existing non-debug fast path.",
  "published": "2026-08-12T00:17:44Z",
  "severity": "",
  "epss": 0.00198,
  "epssPercentile": 0.09564,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.1.6-1",
      "fix": "DEBIAN-CVE-2026-68438",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-68438",
      "released": "2026-08-13T22:19:30Z"
    }
  ],
  "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"
  }
}