CVE-2020-26117

tigervnc: certificate exceptions stored as authorities

Severity Score

8.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

En los archivos rfb/CSecurityTLS.cxx y rfb/CSecurityTLS.java en TigerVNC versiones anteriores a 1.11.0, los espectadores manejan inapropiadamente las excepciones del certificado TLS. Almacenan los certificados como autoridades, lo que significa que el propietario de un certificado puede hacerse pasar por cualquier servidor después de que un cliente haya agregado una excepción

Virtual Network Computing is a remote display system which allows users to view a computing desktop environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures. TigerVNC is a suite of VNC servers and clients.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-09-27 CVE Reserved
2020-09-27 CVE Published
2024-08-04 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-295: Improper Certificate Validation
CWE-296: Improper Following of a Certificate's Chain of Trust

CAPEC

References (11)

URL	Tag	Source
https://bugzilla.opensuse.org/show_bug.cgi?id=1176733	Issue Tracking
https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.0	Release Notes
https://lists.debian.org/debian-lts-announce/2020/10/msg00007.html	Mailing List

URL	Date	SRC

URL	Date	SRC
https://github.com/TigerVNC/tigervnc/commit/20dea801e747318525a5859fe4f37c52b05310cb	2022-11-16
https://github.com/TigerVNC/tigervnc/commit/7399eab79a4365434d26494fa1628ce1eb91562b	2022-11-16
https://github.com/TigerVNC/tigervnc/commit/b30f10c681ec87720cff85d490f67098568a9cba	2022-11-16
https://github.com/TigerVNC/tigervnc/commit/f029745f63ac7d22fb91639b2cb5b3ab56134d6e	2022-11-16

URL	Date	SRC
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00025.html	2022-11-16
http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00024.html	2022-11-16
https://access.redhat.com/security/cve/CVE-2020-26117	2021-05-18
https://bugzilla.redhat.com/show_bug.cgi?id=1882841	2021-05-18

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Tigervnc Search vendor "Tigervnc"		Tigervnc Search vendor "Tigervnc" for product "Tigervnc"				< 1.11.0 Search vendor "Tigervnc" for product "Tigervnc" and version " < 1.11.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Opensuse Search vendor "Opensuse"		Leap Search vendor "Opensuse" for product "Leap"				15.2 Search vendor "Opensuse" for product "Leap" and version "15.2"		-		Affected