CVE-2020-26117

Name: CVE-2020-26117
Creator: NVD / NIST
Published: 2020-09-27T04:15:11.65+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 3.06%

Last modified Jun 17, 2026

CVE-2020-26117 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. In rfb/CSecurityTLS.cxx and rfb/CSecurityTLS.java in TigerVNC before 1.11.0, viewers mishandle TLS certificate exceptions. They store the certificates as authorities, meaning that the owner of a certificate could impersonate any server after a client had added an exception.. EPSS estimates a 3.06% chance of exploitation in the next 30 days.

Description

In rfb/CSecurityTLS.cxx and rfb/CSecurityTLS.java in TigerVNC before 1.11.0, viewers mishandle TLS certificate exceptions. They store the certificates as authorities, meaning that the owner of a certificate could impersonate any server after a client had added an exception.

Metrics

CVSS 3.1

8.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS Probability

3.06%

85.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
Tigervnc	Tigervnc	< 1.11.0
Debian	Debian Linux	9.0
Opensuse	Leap	15.2

References

http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00025.htmlBroken Link, Mailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00024.htmlBroken Link, Mailing List, Third Party Advisory
https://bugzilla.opensuse.org/show_bug.cgi?id=1176733Issue Tracking, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/20dea801e747318525a5859fe4f37c52b05310cbPatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/7399eab79a4365434d26494fa1628ce1eb91562bPatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/b30f10c681ec87720cff85d490f67098568a9cbaPatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/f029745f63ac7d22fb91639b2cb5b3ab56134d6ePatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.0Release Notes, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/10/msg00007.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00025.htmlBroken Link, Mailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00024.htmlBroken Link, Mailing List, Third Party Advisory
https://bugzilla.opensuse.org/show_bug.cgi?id=1176733Issue Tracking, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/20dea801e747318525a5859fe4f37c52b05310cbPatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/7399eab79a4365434d26494fa1628ce1eb91562bPatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/b30f10c681ec87720cff85d490f67098568a9cbaPatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/commit/f029745f63ac7d22fb91639b2cb5b3ab56134d6ePatch, Third Party Advisory
https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.0Release Notes, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/10/msg00007.htmlMailing List, Third Party Advisory

Timeline

Published: Sep 27, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26117?

How severe is CVE-2020-26117?

CVE-2020-26117 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 3.06% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26117?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26117?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST