{
  "threat_severity" : "Moderate",
  "public_date" : "2026-02-14T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: flex_proportions: make fprop_new_period() hardirq safe",
    "id" : "2439941",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2439941"
  },
  "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" : "verified"
  },
  "cwe" : "CWE-833",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nflex_proportions: make fprop_new_period() hardirq safe\nBernd has reported a lockdep splat from flexible proportions code that is\nessentially complaining about the following race:\n<timer fires>\nrun_timer_softirq - we are in softirq context\ncall_timer_fn\nwriteout_period\nfprop_new_period\nwrite_seqcount_begin(&p->sequence);\n<hardirq is raised>\n...\nblk_mq_end_request()\nblk_update_request()\next4_end_bio()\nfolio_end_writeback()\n__wb_writeout_add()\n__fprop_add_percpu_max()\nif (unlikely(max_frac < FPROP_FRAC_BASE)) {\nfprop_fraction_percpu()\nseq = read_seqcount_begin(&p->sequence);\n- sees odd sequence so loops indefinitely\nNote that a deadlock like this is only possible if the bdi has configured\nmaximum fraction of writeout throughput which is very rare in general but\nfrequent for example for FUSE bdis.  To fix this problem we have to make\nsure write section of the sequence counter is irqsafe.", "A deadlock vulnerability was found in the Linux kernel's flexible proportions (fprop) code used for I/O writeback accounting. When a hardirq interrupts the seqcount write section in fprop_new_period() during softirq context, a reader in the hardirq handler can spin indefinitely waiting for the odd sequence number to become even, causing a system hang." ],
  "statement" : "This deadlock primarily affects FUSE filesystems that configure maximum writeback throughput fractions. Standard local filesystems rarely trigger this condition. The issue results in a denial of service (system hang) but cannot be exploited for code execution or data compromise.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "release_date" : "2026-07-21T00:00:00Z",
    "advisory" : "RHSA-2026:42919",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10.2",
    "package" : "kernel-0:6.12.0-211.37.1.el10_2"
  } ],
  "package_state" : [ {
    "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" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-23168\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-23168\nhttps://lore.kernel.org/linux-cve-announce/2026021420-CVE-2026-23168-0630@gregkh/T" ],
  "name" : "CVE-2026-23168",
  "csaw" : false
}