{
  "threat_severity" : "Moderate",
  "public_date" : "2021-05-24T16:00:00Z",
  "bugzilla" : {
    "description" : "kernel: predictable Authvalue in Bluetooth Mesh Provisioning Leads to MITM",
    "id" : "1960009",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1960009"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "status" : "draft"
  },
  "details" : [ "Mesh Provisioning in the Bluetooth Mesh profile 1.0 and 1.0.1 may permit a nearby device (without possession of the AuthValue used in the provisioning protocol) to determine the AuthValue via a brute-force attack (unless the AuthValue is sufficiently random and changed each time).", "A flaw was found in the Linux kernel’s Bluetooth Mesh Profile implementation. The Mesh Provisioning procedure has a vulnerability that allows an attacker observing or taking part in the provisioning to brute force the AuthValue if it has a fixed value or is selected predictably or with low entropy. If successful, an attacker can identify the AuthValue and authenticate to both the Provisioner and provisioned devices, allowing a Man-in-the-Middle (MITM) attack on a future provisioning attempt with the same AuthValue. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability." ],
  "statement" : "Red Hat Product Security is aware of this issue and is currently assessing the impact on Red Hat supported products. Corresponding entry in the Red Hat CVE database (https://access.redhat.com/security/security-updates/#/cve) will be updated with latest information as the assessment progresses.",
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Out of support scope",
    "package_name" : "bluez",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "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" : "Out of support scope",
    "package_name" : "bluez",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "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-alt",
    "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" : "Will not fix",
    "package_name" : "bluez",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "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" : "Will not fix",
    "package_name" : "bluez",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "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-2020-26557\nhttps://nvd.nist.gov/vuln/detail/CVE-2020-26557" ],
  "name" : "CVE-2020-26557",
  "mitigation" : {
    "value" : "It is recommended for devices to use AuthValues containing the maximum entropy permitted (128-bits) and randomly select a new AuthValue using a secure random number generator with each new provisioning attempt.  A large entropy helps ensure that a brute-force of the AuthValue, even a static AuthValue, cannot normally be completed in a reasonable time.",
    "lang" : "en:us"
  },
  "csaw" : false
}