Skip to content
Fencer Intel
medium 5.8

CVE-2011-1775 json

The CSecurityTLS::processMsg function in common/rfb/CSecurityTLS.cxx in the vncviewer component in TigerVNC 1.1beta1 does not properly veri…

published 2011-05-26 15 y ago modified 2026-06-16 4 mo ago also EUVD-2011-1773

cvss
5.8
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

The CSecurityTLS::processMsg function in common/rfb/CSecurityTLS.cxx in the vncviewer component in TigerVNC 1.1beta1 does not properly verify the server's X.509 certificate, which allows man-in-the-middle attackers to spoof a TLS VNC server via an arbitrary certificate.

Patch / fix

  • tigervnc RHEL 6 1.0.90-0.15.20110314svn4359.el6_1.1
  • tigervnc-server RHEL 6 1.0.90-0.15.20110314svn4359.el6_1.1
  • tigervnc-server-applet RHEL 6 1.0.90-0.15.20110314svn4359.el6_1.1
  • tigervnc-server-module RHEL 6 1.0.90-0.15.20110314svn4359.el6_1.1

red hat advisories RHSA-2011:0871

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2011-1775 updated cvss 2.6

tigervnc: vncviewer can send password to server without proper validation of the X.509 certificate

  • Red Hat Enterprise Linux Server (v. 6) tigervnc 1.0.90-0.15.20110314svn4359.el6_1.1, tigervnc-server 1.0.90-0.15.20110314svn4359.el6_1.1, tigervnc-server-applet 1.0.90-0.15.20110314svn4359.el6_1.1, tigervnc-server-module 1.0.90-0.15.20110314svn4359.el6_1.1 Red Hat Enterprise Linux Server Optional (v. 6) tigervnc 1.0.90-0.15.20110314svn4359.el6_1.1, tigervnc-server 1.0.90-0.15.20110314svn4359.el6_1.1, tigervnc-server-applet 1.0.90-0.15.20110314svn4359.el6_1.1, tigervnc-server-module 1.0.90-0.15.20110314svn4359.el6_1.1
    fixed: vendor fix RHSA-2011:0871

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.29% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.