{
  "cveId": "CVE-2026-93253",
  "url": "https://patchblox.com/security/cve/CVE-2026-93253",
  "summary": "CVE-2026-93253 is fixed in linux on 1 platform by DEBIAN-CVE-2026-93253 (version 7.2.6-1), released September 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  sched/isolation: Defer freeing of cpumask memblo...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  sched/isolation: Defer freeing of cpumask memblock memory to initcall  When testing a linux-next kernel with commit 59bd1d914bb5 (\u0022memblock: warn when freeing reserved memory before memory map is initialized\u0022), the following warning was hit when there was a \u0022nohz_full\u0022 kernel boot parameter.    Cannot free reserved memory because of deferred initialization of the memory map   WARNING: mm/memblock.c:904 at __free_reserved_area\u002B0xde/0xf0, CPU#0: swapper/0/0     :   Call Trace:    \u003CTASK\u003E    memblock_phys_free\u002B0xcb/0x100    housekeeping_init\u002B0x14c/0x170    start_kernel\u002B0x207/0x450    x86_64_start_reservations\u002B0x24/0x30    x86_64_start_kernel\u002B0xda/0xe0    common_startup_64\u002B0x13e/0x141    \u003C/TASK\u003E  IOW, we shouldn\u0027t free memblock allocated memory so early in the boot process when memory map isn\u0027t fully initialized in deferred_init_memmap().  Fix it by saving the housekeeping cpumask memblock memory to be freed into a llist free list in housekeeping_init() and add a new housekeeping_late_init() helper to defer the actual freeing of memblock memory to when initcall\u0027s are being processed. The cpumask memblock memory is treated as a llist_node with the size of a \u0022long\u0022 type which is also smallest cpumask size that can be allocated.  The non-atomic version of the llist APIs are used as there is no contention.  This commit depends on the presence of commit 7c2eee9c1367 (\u0022memblock: don\u0027t touch memblock arrays when memblock_free() is called late\u0022) to prevent a KASAN UAF bug report [1].   [1] https://lore.kernel.org/lkml/20260505051821.1107133-1-longman@redhat.com/",
  "published": "2026-09-24T16:17:21Z",
  "severity": "",
  "epss": 0.00189,
  "epssPercentile": 0.08634,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-93253",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-93253",
      "released": "2026-09-24T19:30:44Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}