{
  "threat_severity" : "Important",
  "public_date" : "2023-09-05T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: use-after-free in sch_qfq network scheduler",
    "id" : "2245514",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2245514"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.8",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-416",
  "details" : [ "A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation.\nWhen the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue().\nWe recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.", "A use-after-free flaw was found in qfq_dequeue and agg_dequeue in net/sched/sch_qfq.c in the Traffic Control (QoS) subsystem in the Linux kernel. This issue may allow a local user to crash the system or escalate their privileges on the system." ],
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 6 Extended Lifecycle Support",
    "release_date" : "2024-04-16T00:00:00Z",
    "advisory" : "RHSA-2024:1831",
    "cpe" : "cpe:/o:redhat:rhel_els:6",
    "package" : "kernel-0:2.6.32-754.53.1.el6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "release_date" : "2024-03-14T00:00:00Z",
    "advisory" : "RHSA-2024:1332",
    "cpe" : "cpe:/a:redhat:rhel_extras_rt:7",
    "package" : "kernel-rt-0:3.10.0-1160.114.2.rt56.1266.el7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "release_date" : "2024-03-12T00:00:00Z",
    "advisory" : "RHSA-2024:1249",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7",
    "package" : "kernel-0:3.10.0-1160.114.2.el7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "release_date" : "2024-03-13T00:00:00Z",
    "advisory" : "RHSA-2024:1323",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7",
    "package" : "kpatch-patch"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7.6 Advanced Update Support(Disable again in 2026 - SPRHEL-7118)",
    "release_date" : "2024-02-26T00:00:00Z",
    "advisory" : "RHSA-2024:0980",
    "cpe" : "cpe:/o:redhat:rhel_aus:7.6",
    "package" : "kernel-0:3.10.0-957.111.1.el7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7.7 Advanced Update Support",
    "release_date" : "2024-02-27T00:00:00Z",
    "advisory" : "RHSA-2024:0999",
    "cpe" : "cpe:/o:redhat:rhel_aus:7.7",
    "package" : "kernel-0:3.10.0-1062.85.1.el7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2024-02-20T00:00:00Z",
    "advisory" : "RHSA-2024:0881",
    "cpe" : "cpe:/a:redhat:enterprise_linux:8::nfv",
    "package" : "kernel-rt-0:4.18.0-513.18.1.rt7.320.el8_9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2024-02-20T00:00:00Z",
    "advisory" : "RHSA-2024:0876",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kpatch-patch"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2024-02-20T00:00:00Z",
    "advisory" : "RHSA-2024:0897",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kernel-0:4.18.0-513.18.1.el8_9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Advanced Update Support",
    "release_date" : "2024-03-12T00:00:00Z",
    "advisory" : "RHSA-2024:1268",
    "cpe" : "cpe:/o:redhat:rhel_aus:8.2",
    "package" : "kernel-0:4.18.0-193.128.1.el8_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Telecommunications Update Service",
    "release_date" : "2024-03-12T00:00:00Z",
    "advisory" : "RHSA-2024:1269",
    "cpe" : "cpe:/a:redhat:rhel_tus:8.2::nfv",
    "package" : "kernel-rt-0:4.18.0-193.128.1.rt13.179.el8_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Telecommunications Update Service",
    "release_date" : "2024-03-12T00:00:00Z",
    "advisory" : "RHSA-2024:1268",
    "cpe" : "cpe:/o:redhat:rhel_tus:8.2",
    "package" : "kernel-0:4.18.0-193.128.1.el8_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions",
    "release_date" : "2024-03-12T00:00:00Z",
    "advisory" : "RHSA-2024:1268",
    "cpe" : "cpe:/o:redhat:rhel_e4s:8.2",
    "package" : "kernel-0:4.18.0-193.128.1.el8_2"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions",
    "release_date" : "2024-03-12T00:00:00Z",
    "advisory" : "RHSA-2024:1278",
    "cpe" : "cpe:/o:redhat:rhel_e4s:8.2",
    "package" : "kpatch-patch"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support",
    "release_date" : "2024-01-30T00:00:00Z",
    "advisory" : "RHSA-2024:0562",
    "cpe" : "cpe:/o:redhat:rhel_aus:8.4",
    "package" : "kernel-0:4.18.0-305.120.1.el8_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Telecommunications Update Service",
    "release_date" : "2024-01-30T00:00:00Z",
    "advisory" : "RHSA-2024:0563",
    "cpe" : "cpe:/a:redhat:rhel_tus:8.4::nfv",
    "package" : "kernel-rt-0:4.18.0-305.120.1.rt7.196.el8_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Telecommunications Update Service",
    "release_date" : "2024-01-30T00:00:00Z",
    "advisory" : "RHSA-2024:0562",
    "cpe" : "cpe:/o:redhat:rhel_tus:8.4",
    "package" : "kernel-0:4.18.0-305.120.1.el8_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions",
    "release_date" : "2024-01-30T00:00:00Z",
    "advisory" : "RHSA-2024:0562",
    "cpe" : "cpe:/o:redhat:rhel_e4s:8.4",
    "package" : "kernel-0:4.18.0-305.120.1.el8_4"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions",
    "release_date" : "2024-01-30T00:00:00Z",
    "advisory" : "RHSA-2024:0593",
    "cpe" : "cpe:/o:redhat:rhel_e4s:8.4",
    "package" : "kpatch-patch"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.6 Extended Update Support",
    "release_date" : "2024-02-07T00:00:00Z",
    "advisory" : "RHSA-2024:0724",
    "cpe" : "cpe:/o:redhat:rhel_eus:8.6",
    "package" : "kernel-0:4.18.0-372.91.1.el8_6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.6 Extended Update Support",
    "release_date" : "2024-02-15T00:00:00Z",
    "advisory" : "RHSA-2024:0851",
    "cpe" : "cpe:/o:redhat:rhel_eus:8.6",
    "package" : "kpatch-patch"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.8 Extended Update Support",
    "release_date" : "2024-03-19T00:00:00Z",
    "advisory" : "RHSA-2024:1368",
    "cpe" : "cpe:/o:redhat:rhel_eus:8.8",
    "package" : "kpatch-patch"
  }, {
    "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 Virtualization 4 for Red Hat Enterprise Linux 8",
    "release_date" : "2024-02-07T00:00:00Z",
    "advisory" : "RHSA-2024:0724",
    "cpe" : "cpe:/o:redhat:rhev_hypervisor:4.4::el8",
    "package" : "kernel-0:4.18.0-372.91.1.el8_6"
  } ],
  "package_state" : [ {
    "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-2023-4921\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-4921\nhttps://github.com/torvalds/linux/commit/8fc134fee27f2263988ae38920bc03da416b03d8" ],
  "name" : "CVE-2023-4921",
  "mitigation" : {
    "value" : "Mitigation for this issue is to skip loading the affected module sch_qfq onto the system until we have a fix available. This can be done by a blacklist mechanism and will ensure the driver is not loaded at the boot time.\n~~~\nHow do I blacklist a kernel module to prevent it from loading automatically? \nhttps://access.redhat.com/solutions/41278  \n~~~",
    "lang" : "en:us"
  },
  "csaw" : false
}