Improper Following of a Certificate's Chain of Trust Affecting tigervnc-server package, versions <0:1.11.0-6.el8


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.19% (57th percentile)

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  • Snyk IDSNYK-RHEL8-TIGERVNCSERVER-4007367
  • published26 Jul 2021
  • disclosed18 Sept 2020

Introduced: 18 Sep 2020

CVE-2020-26117  (opens in a new tab)
CWE-296  (opens in a new tab)

How to fix?

Upgrade RHEL:8 tigervnc-server to version 0:1.11.0-6.el8 or higher.
This issue was patched in RHSA-2021:1783.

NVD Description

Note: Versions mentioned in the description apply only to the upstream tigervnc-server package and not the tigervnc-server package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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.

CVSS Scores

version 3.1