{
  "cveId": "CVE-2018-21247",
  "url": "https://patchblox.com/security/cve/CVE-2018-21247",
  "summary": "CVE-2018-21247 is fixed in 2 products on 1 platform, first by RHSA-2021:1811, released May 18, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "libvncserver: LibVNCServer is a C library that enables you to implement VNC server functionality into own programs.\n\nSecurity Fix(e...",
  "description": "LibVNCServer is a C library that enables you to implement VNC server functionality into own programs.\n\nSecurity Fix(es):\n\n* libvncserver: uninitialized memory contents are vulnerable to Information Leak (CVE-2018-21247)\n\n* libvncserver: buffer overflow in ConnectClientToUnixSock() (CVE-2019-20839)\n\n* libvncserver: libvncserver/rfbregion.c has a NULL pointer dereference (CVE-2020-14397)\n\n* libvncserver: libvncclient/rfbproto.c does not limit TextChat size (CVE-2020-14405)\n\n* libvncserver: libvncserver/rfbserver.c has a divide by zero which could result in DoS (CVE-2020-25708)\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.\n\nAdditional Changes:\n\nFor detailed information on changes in this release, see the Red Hat Enterprise Linux 8.4 Release Notes linked from the References section.",
  "published": "2021-05-18T00:00:00Z",
  "severity": "Moderate",
  "cvss": 7.5,
  "epss": 0.02516,
  "epssPercentile": 0.84917,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libvncserver",
      "release": "RHEL 8",
      "fixedVersion": "0:0.9.11-17.el8",
      "fix": "RHSA-2021:1811",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-1811",
      "released": "2021-05-18T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libvncserver",
      "release": "ol 8",
      "fixedVersion": "0:0.9.11-17.el8",
      "fix": "ELSA-2021-1811",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-1811",
      "released": "2021-05-25T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libvncserver-devel",
      "release": "RHEL 8",
      "fixedVersion": "0:0.9.11-17.el8",
      "fix": "RHSA-2021:1811",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-1811",
      "released": "2021-05-18T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "libvncserver-devel",
      "release": "ol 8",
      "fixedVersion": "0:0.9.11-17.el8",
      "fix": "ELSA-2021-1811",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-1811",
      "released": "2021-05-25T00:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-07T18:46:35Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}