CVE-2018-20021

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

3.52% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 88.4% of scored records. A rank, not a probability.

NVD base score

7.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Low. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2018-12-19 16:00Z7 YR AGO

Last updated

2024-08-05 11:51Z2 YR AGO

Reserved

2018-12-10

Assigning CNA

Kaspersky

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')Base
• CWE-400Uncontrolled Resource ConsumptionClass

Data version

5.1

Document digest

124d30758ca6dce3aeb102d30b102b21c747532501ec96f83be8c38eaf08fd1c

• www.debian.orgDSA-4383https://www.debian.org/security/2019/dsa-4383vendor-advisoryx_refsource_DEBIAN
• lists.debian.org[debian-lts-announce] 20181227 [SECURITY] [DLA 1617-1] libvncserver security updatehttps://lists.debian.org/debian-lts-announce/2018/12/msg00017.htmlmailing-listx_refsource_MLIST
• ics-cert.kaspersky.comhttps://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/x_refsource_MISC
• usn.ubuntu.comUSN-3877-1https://usn.ubuntu.com/3877-1/vendor-advisoryx_refsource_UBUNTU
• security.gentoo.orgGLSA-201908-05https://security.gentoo.org/glsa/201908-05vendor-advisoryx_refsource_GENTOO
• lists.debian.org[debian-lts-announce] 20191030 [SECURITY] [DLA 1979-1] italc security updatehttps://lists.debian.org/debian-lts-announce/2019/10/msg00042.htmlmailing-listx_refsource_MLIST
• lists.debian.org[debian-lts-announce] 20191129 [SECURITY] [DLA 2016-1] ssvnc security updatehttps://lists.debian.org/debian-lts-announce/2019/11/msg00033.htmlmailing-listx_refsource_MLIST
• lists.debian.org[debian-lts-announce] 20191221 [SECURITY] [DLA 2045-1] tightvnc security updatehttps://lists.debian.org/debian-lts-announce/2019/12/msg00028.htmlmailing-listx_refsource_MLIST
• security.gentoo.orgGLSA-202006-06https://security.gentoo.org/glsa/202006-06vendor-advisoryx_refsource_GENTOO
• usn.ubuntu.comUSN-4547-1https://usn.ubuntu.com/4547-1/vendor-advisoryx_refsource_UBUNTU
• usn.ubuntu.comUSN-4547-2https://usn.ubuntu.com/4547-2/vendor-advisoryx_refsource_UBUNTU
• usn.ubuntu.comUSN-4587-1https://usn.ubuntu.com/4587-1/vendor-advisoryx_refsource_UBUNTU