CVE-2018-20021
LibVNC before commit c3115350eb8bb635d0fdb4dbbb0d0541f38ed19c contains a CWE-835: Infinite loop vulnerability in VNC client code.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.42%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
LibVNC before commit c3115350eb8bb635d0fdb4dbbb0d0541f38ed19c contains a CWE-835: Infinite loop vulnerability in VNC client code. Vulnerability allows attacker to consume excessive amount of resources like CPU and RAM
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 3.42% probability · 89th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-835
- Affected
- libvnc project/libvncserver · canonical/ubuntu linux · debian/debian linux
- Source
- vulnerability@kaspersky.com
EPSS 3.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2018/12/msg00017.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
- https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html
- https://lists.debian.org/debian-lts-announce/2019/12/msg00028.html
- https://security.gentoo.org/glsa/201908-05
- https://security.gentoo.org/glsa/202006-06
- https://usn.ubuntu.com/3877-1/Third Party Advisory
- https://usn.ubuntu.com/4547-1/
- https://usn.ubuntu.com/4547-2/
- https://usn.ubuntu.com/4587-1/
- https://www.debian.org/security/2019/dsa-4383Third Party Advisory
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-031-libvnc-infinite-loop/Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2018/12/msg00017.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
- https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html
- https://lists.debian.org/debian-lts-announce/2019/12/msg00028.html
- https://security.gentoo.org/glsa/201908-05
- https://security.gentoo.org/glsa/202006-06
- https://usn.ubuntu.com/3877-1/Third Party Advisory
- https://usn.ubuntu.com/4547-1/
- https://usn.ubuntu.com/4547-2/
- https://usn.ubuntu.com/4587-1/
- https://www.debian.org/security/2019/dsa-4383Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.