A vulnerability was discovered in tigernvc, a Virtual Network Computing client and server implementation. The viewer implementation mishandles TLS certificate exceptions, storing the certificates as authorities, meaning that the owner of a certificate could impersonate any server after a client had added an exception.

For Debian 9 stretch, this problem has been fixed in version 1.7.0+dfsg-7+deb9u2.

We recommend that you upgrade your tigervnc packages.

For the detailed security status of tigervnc please refer to its security tracker page at: https://security-tracker.debian.org/tracker/tigervnc

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS