{
  "threat_severity" : "Moderate",
  "public_date" : "2020-11-09T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: slab-out-of-bounds read in fbcon",
    "id" : "1903126",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1903126"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.0",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-125",
  "details" : [ "A slab-out-of-bounds read in fbcon in the Linux kernel before 5.9.7 could be used by local attackers to read privileged information or potentially crash the kernel, aka CID-3c4e0dff2095. This occurs because KD_FONT_OP_COPY in drivers/tty/vt/vt.c can be used for manipulations such as font height.", "An out-of-bounds (OOB) SLAB memory access flaw was found in the Linux kernel's fbcon driver module. A bounds check failure allows a local attacker with special user privileges to gain access to out-of-bounds memory, leading to a system crash or leaking of internal kernel information. The highest threat from this vulnerability is to system availability." ],
  "acknowledgement" : "Red Hat would like to thank Yuan Ming <yuanmingbuaa@gmail com> (Tsinghua University) for reporting this issue.",
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2021-05-18T00:00:00Z",
    "advisory" : "RHSA-2021:1739",
    "cpe" : "cpe:/a:redhat:enterprise_linux:8::nfv",
    "package" : "kernel-rt-0:4.18.0-305.rt7.72.el8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "release_date" : "2021-05-18T00:00:00Z",
    "advisory" : "RHSA-2021:1578",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8",
    "package" : "kernel-0:4.18.0-305.el8"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 5",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:5"
  }, {
    "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" : "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-alt",
    "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 MRG 2",
    "fix_state" : "Will not fix",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/a:redhat:enterprise_mrg:2"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2020-28974\nhttps://nvd.nist.gov/vuln/detail/CVE-2020-28974" ],
  "name" : "CVE-2020-28974",
  "mitigation" : {
    "value" : "Add 'nomodeset' option as kernel boot parameter to disable frame buffering in /etc/default/grub, and run 'grub2-mkconfig -o /boot/grub2/grub.cfg' and reboot.\n~~~\n# cat /proc/cmdline \nBOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-147.el8.x86_64 root=/dev/mapper/rhel_rhel8u2--1-root ro crashkernel=auto resume=/dev/mapper/rhel_rhel8u2--1-swap rd.lvm.lv=rhel_rhel8u2-1/root rd.lvm.lv=rhel_rhel8u2-1/swap nomodeset\n# ls -l /dev/fb*\nls: cannot access '/dev/fb*': No such file or directory\n~~~\nThe above said mitigation does not so effect for rhel6 kernel , and is only applicable for rhel7/8.",
    "lang" : "en:us"
  },
  "csaw" : false
}