CVE-2020-26117: n/a vulnerability

CVE-2020-26117: In rfb/CSecurityTLS.cxx and rfb/CSecurityTLS.java in TigerVNC before 1.11.0, viewers mishandle TLS certific...

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.

UnknownCVSS not scoredNot KEV-listedUpdatedAug 4, 2024, 15:49 UTC (UTC+00:00)

Security readout for executives and security teams

TigerVNC viewers before 1.11.0 handled TLS certificate exceptions too broadly. If a user accepted one certificate exception, that certificate could become trusted like an authority, allowing its owner to impersonate other VNC servers to that client. Exposure is limited to TigerVNC viewer deployments before 1.11.0, particularly clients that accepted TLS certificate exceptions. Systems using vendor-patched TigerVNC packages from Debian or openSUSE advisories may already be remediated. Treat this as a targeted remote-access trust issue, not a broad internet worm risk. Prioritize environments where TigerVNC supports administration, sensitive systems, or third-party access, because server impersonation can expose credentials or sessions. Mitigation focus: Upgrade TigerVNC viewers to 1.11.0 or a vendor-patched package.; Apply Debian or openSUSE security updates where those distributions manage TigerVNC.; Review and remove old TigerVNC TLS certificate exceptions where feasible..

Prepared: Jun 5, 2026, 14:11 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record

Severity: Unknown
CVSS: Not scored
Known Exploited: No
Published: Sep 27, 2020, 03:30 UTC (UTC+00:00)

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors

0Timeline events

0ADP providers

8Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

CVE List V5 sourceCVE List V5
https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.0CVE reference · x_refsource_MISC
https://github.com/TigerVNC/tigervnc/commit/f029745f63ac7d22fb91639b2cb5b3ab56134d6eCVE reference · x_refsource_MISC
https://github.com/TigerVNC/tigervnc/commit/b30f10c681ec87720cff85d490f67098568a9cbaCVE reference · x_refsource_MISC
https://github.com/TigerVNC/tigervnc/commit/20dea801e747318525a5859fe4f37c52b05310cbCVE reference · x_refsource_MISC
https://github.com/TigerVNC/tigervnc/commit/7399eab79a4365434d26494fa1628ce1eb91562bCVE reference · x_refsource_MISC
https://bugzilla.opensuse.org/show_bug.cgi?id=1176733CVE reference · x_refsource_MISC
[debian-lts-announce] 20201006 [SECURITY] [DLA 2396-1] tigervnc security updateCVE reference · mailing-list, x_refsource_MLIST

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus

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Weakness

CWE details

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