CVE-2020-26117 Security feature bypass in n/a

High 8.1 Published Updated

TigerVNC viewers mishandle TLS certificate exceptions, allowing certificate owners to impersonate servers after a user adds an exception.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
A user has to click or open something
Fix
Available

What is CVE-2020-26117?

CVE-2020-26117 is a high-severity vulnerability in Debian Debian Linux, published on 27 Sep 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official 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.

Weakness: CWE-295

Which versions are affected by CVE-2020-26117?

It affects 3 products.

Linux distribution packages (40)
tigervnc Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-debugsource Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-icons Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-license Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-selinux Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-server Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-server-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-server-minimal Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-server-minimal-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-server-module Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc-server-module-debuginfo Red Hat:enterprise_linux:8::appstreamAll versions0:1.11.0-6.el8
tigervnc Rocky Linux:8All versions0:1.11.0-6.el8
tigervnc SUSE:Enterprise Storage 5All versions1.6.0-27.1
tigervnc SUSE:HPE Helion OpenStack 8All versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise High Performance Computing 15-ESPOSAll versions1.8.0-13.14.1
tigervnc SUSE:Linux Enterprise High Performance Computing 15-LTSSAll versions1.8.0-13.14.1
tigervnc SUSE:Linux Enterprise Module for Basesystem 15 SP1All versions1.9.0-19.9.1
tigervnc SUSE:Linux Enterprise Module for Basesystem 15 SP2All versions1.9.0-19.9.1
tigervnc SUSE:Linux Enterprise Module for Desktop Applications 15 SP1All versions1.9.0-19.9.1
tigervnc SUSE:Linux Enterprise Module for Desktop Applications 15 SP2All versions1.9.0-19.9.1
tigervnc SUSE:Linux Enterprise Server 12 SP2-BCLAll versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise Server 12 SP2-LTSSAll versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise Server 12 SP3-BCLAll versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise Server 12 SP3-LTSSAll versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise Server 12 SP4-LTSSAll versions1.6.0-22.17.1
tigervnc SUSE:Linux Enterprise Server 12 SP5All versions1.6.0-22.17.1
tigervnc SUSE:Linux Enterprise Server 15-LTSSAll versions1.8.0-13.14.1
tigervnc SUSE:Linux Enterprise Server for SAP Applications 12 SP2All versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise Server for SAP Applications 12 SP3All versions1.6.0-27.1
tigervnc SUSE:Linux Enterprise Server for SAP Applications 12 SP4All versions1.6.0-22.17.1
tigervnc SUSE:Linux Enterprise Server for SAP Applications 12 SP5All versions1.6.0-22.17.1
tigervnc SUSE:Linux Enterprise Server for SAP Applications 15All versions1.8.0-13.14.1
tigervnc SUSE:OpenStack Cloud 7All versions1.6.0-27.1
tigervnc SUSE:OpenStack Cloud 8All versions1.6.0-27.1
tigervnc SUSE:OpenStack Cloud 9All versions1.6.0-22.17.1
tigervnc SUSE:OpenStack Cloud Crowbar 8All versions1.6.0-27.1
tigervnc SUSE:OpenStack Cloud Crowbar 9All versions1.6.0-22.17.1
tigervnc openSUSE:Leap 15.1All versions1.9.0-lp151.4.9.1
tigervnc openSUSE:Leap 15.2All versions1.9.0-lp152.7.3.1

Products include Debian Debian Linux, Opensuse Leap, Tigervnc Tigervnc.

How do I fix CVE-2020-26117?

Upgrade to a fixed version.

Is CVE-2020-26117 being exploited?

There is no known exploitation of CVE-2020-26117 in the wild and no public exploit code.

All Debian Debian Linux vulnerabilities

Sources

Also known as DEBIAN-CVE-2020-26117, DLA-2396-1, GHSA-cx25-8g49-fx7q, MGASA-2020-0388, RHSA-2021:1783, RLSA-2021:1783 and 8 more.

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