{
  "threat_severity" : "Moderate",
  "public_date" : "2025-09-18T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: blk-cgroup: Reinit blkg_iostat_set after clearing in blkcg_reset_stats()",
    "id" : "2396500",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2396500"
  },
  "cvss3" : {
    "cvss3_base_score" : "4.4",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-476",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nblk-cgroup: Reinit blkg_iostat_set after clearing in blkcg_reset_stats()\nWhen blkg_alloc() is called to allocate a blkcg_gq structure\nwith the associated blkg_iostat_set's, there are 2 fields within\nblkg_iostat_set that requires proper initialization - blkg & sync.\nThe former field was introduced by commit 3b8cc6298724 (\"blk-cgroup:\nOptimize blkcg_rstat_flush()\") while the later one was introduced by\ncommit f73316482977 (\"blk-cgroup: reimplement basic IO stats using\ncgroup rstat\").\nUnfortunately those fields in the blkg_iostat_set's are not properly\nre-initialized when they are cleared in v1's blkcg_reset_stats(). This\ncan lead to a kernel panic due to NULL pointer access of the blkg\npointer. The missing initialization of sync is less problematic and\ncan be a problem in a debug kernel due to missing lockdep initialization.\nFix these problems by re-initializing them after memory clearing." ],
  "statement" : "The bug stems from clearing per-CPU blkg_iostat_set structures in blkcg_reset_stats() without re-initializing required fields (blkg pointer and sync stats), leading to a possible NULL dereference and kernel panic when stats are accessed later. Triggering this requires privileged access to the blk-cgroup interface (e.g., resetting stats), so it’s not remotely exploitable. Impact is a local DoS.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2023-11-14T00:00:00Z",
    "advisory" : "RHSA-2023:7077",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kernel-0:4.18.0-513.5.1.el8_9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.8 Extended Update Support",
    "release_date" : "2024-03-19T00:00:00Z",
    "advisory" : "RHSA-2024:1404",
    "cpe" : "cpe:/o:redhat:rhel_eus:8.8",
    "package" : "kernel-0:4.18.0-477.51.1.el8_8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2024-04-30T00:00:00Z",
    "advisory" : "RHSA-2024:2394",
    "cpe" : "cpe:/a:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-427.13.1.el9_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "release_date" : "2024-04-30T00:00:00Z",
    "advisory" : "RHSA-2024:2394",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9",
    "package" : "kernel-0:5.14.0-427.13.1.el9_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9.2 Extended Update Support",
    "release_date" : "2024-07-24T00:00:00Z",
    "advisory" : "RHSA-2024:4823",
    "cpe" : "cpe:/a:redhat:rhel_eus:9.2",
    "package" : "kernel-0:5.14.0-284.75.1.el9_2"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Out of support scope",
    "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" : "Fix deferred",
    "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-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2023-53421\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53421\nhttps://lore.kernel.org/linux-cve-announce/2025091855-CVE-2023-53421-0dd9@gregkh/T" ],
  "name" : "CVE-2023-53421",
  "csaw" : false
}