{
  "threat_severity" : "Moderate",
  "public_date" : "2025-07-09T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: lib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()",
    "id" : "2378995",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2378995"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-476",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nlib/group_cpus: fix NULL pointer dereference from group_cpus_evenly()\nWhile testing null_blk with configfs, echo 0 > poll_queues will trigger\nfollowing panic:\nBUG: kernel NULL pointer dereference, address: 0000000000000010\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 27 UID: 0 PID: 920 Comm: bash Not tainted 6.15.0-02023-gadbdb95c8696-dirty #1238 PREEMPT(undef)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014\nRIP: 0010:__bitmap_or+0x48/0x70\nCall Trace:\n<TASK>\n__group_cpus_evenly+0x822/0x8c0\ngroup_cpus_evenly+0x2d9/0x490\nblk_mq_map_queues+0x1e/0x110\nnull_map_queues+0xc9/0x170 [null_blk]\nblk_mq_update_queue_map+0xdb/0x160\nblk_mq_update_nr_hw_queues+0x22b/0x560\nnullb_update_nr_hw_queues+0x71/0xf0 [null_blk]\nnullb_device_poll_queues_store+0xa4/0x130 [null_blk]\nconfigfs_write_iter+0x109/0x1d0\nvfs_write+0x26e/0x6f0\nksys_write+0x79/0x180\n__x64_sys_write+0x1d/0x30\nx64_sys_call+0x45c4/0x45f0\ndo_syscall_64+0xa5/0x240\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nRoot cause is that numgrps is set to 0, and ZERO_SIZE_PTR is returned from\nkcalloc(), and later ZERO_SIZE_PTR will be deferenced.\nFix the problem by checking numgrps first in group_cpus_evenly(), and\nreturn NULL directly if numgrps is zero.\n[yukuai3@huawei.com: also fix the non-SMP version]" ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2025-38255\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-38255\nhttps://lore.kernel.org/linux-cve-announce/2025070935-CVE-2025-38255-57aa@gregkh/T" ],
  "name" : "CVE-2025-38255",
  "csaw" : false
}