What’s Vulnerable › Vulnerabilities

CVE-2020-26117

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-27 · updated 2026-06-17
• Weakness: CWE-295

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.

Affected products

• Debian Linux: 9.0
• openSUSE Leap: 15.2
• Kaspersky TigerVNC: before 1.11.0 — fixed in 1.11.0

How to fix

Upgrade to a fixed version: Kaspersky TigerVNC 1.11.0. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00025.html
• http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00024.html
• https://bugzilla.opensuse.org/show_bug.cgi?id=1176733
• https://github.com/TigerVNC/tigervnc/commit/20dea801e747318525a5859fe4f37c52b05310cb
• https://github.com/TigerVNC/tigervnc/commit/7399eab79a4365434d26494fa1628ce1eb91562b
• https://github.com/TigerVNC/tigervnc/commit/b30f10c681ec87720cff85d490f67098568a9cba
• https://github.com/TigerVNC/tigervnc/commit/f029745f63ac7d22fb91639b2cb5b3ab56134d6e
• https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.0
• https://lists.debian.org/debian-lts-announce/2020/10/msg00007.html
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00025.html
• http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00024.html
• https://bugzilla.opensuse.org/show_bug.cgi?id=1176733

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