{
  "threat_severity" : "Moderate",
  "public_date" : "2021-09-23T16:20:00Z",
  "bugzilla" : {
    "description" : "kernel: timer tree corruption leads to missing wakeup and system freeze",
    "id" : "2005258",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2005258"
  },
  "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-665",
  "details" : [ "A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueue_add function in lib/timerqueue.c. This flaw allows a local attacker with special user privileges to cause a denial of service, slowing and eventually stopping the system while running OSP.", "A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueue_add function in lib/timerqueue.c. This flaw allows a local attacker with special user privileges to cause a denial of service, slowing and eventually stopping the system while running OSP. The highest threat from this vulnerability is system availability." ],
  "acknowledgement" : "This issue was discovered by Jay Shin (Red Hat).",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2021-11-15T00:00:00Z",
    "advisory" : "RHSA-2021:4646",
    "cpe" : "cpe:/a:redhat:enterprise_linux:8::nfv",
    "package" : "kernel-rt-0:4.18.0-348.2.1.rt7.132.el8_5"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2021-11-15T00:00:00Z",
    "advisory" : "RHSA-2021:4647",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kernel-0:4.18.0-348.2.1.el8_5"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Extended Update Support",
    "release_date" : "2021-11-30T00:00:00Z",
    "advisory" : "RHSA-2021:4875",
    "cpe" : "cpe:/a:redhat:rhel_eus:8.2::nfv",
    "package" : "kernel-rt-0:4.18.0-193.70.1.rt13.120.el8_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Extended Update Support",
    "release_date" : "2021-11-30T00:00:00Z",
    "advisory" : "RHSA-2021:4871",
    "cpe" : "cpe:/o:redhat:rhel_eus:8.2",
    "package" : "kernel-0:4.18.0-193.70.1.el8_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Extended Update Support",
    "release_date" : "2021-11-15T00:00:00Z",
    "advisory" : "RHSA-2021:4648",
    "cpe" : "cpe:/a:redhat:rhel_eus:8.4::nfv",
    "package" : "kernel-rt-0:4.18.0-305.28.1.rt7.100.el8_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Extended Update Support",
    "release_date" : "2021-11-15T00:00:00Z",
    "advisory" : "RHSA-2021:4650",
    "cpe" : "cpe:/o:redhat:rhel_eus:8.4",
    "package" : "kernel-0:4.18.0-305.28.1.el8_4"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 5",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:5"
  }, {
    "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" : "Will not fix",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Will not fix",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2021-20317\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-20317\nhttps://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=511885d7061eda3eb1faf3f57dcc936ff75863f1" ],
  "name" : "CVE-2021-20317",
  "mitigation" : {
    "value" : "In order to mitigate this issue, it is possible to prevent the affected code by loading the kvm module with \"pi_inject_timer=0\" parameter.\n~~~\nrmmod kvm_intel kvm\nmodprobe kvm pi_inject_timer=0 \nmodprobe kvm_intel\n~~~",
    "lang" : "en:us"
  },
  "csaw" : false
}