TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which occurs in TightDecoder::FilterGradient. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity.
https://github.com/TigerVNC/tigervnc/releases/tag/v1.10.1
https://github.com/CendioOssman/tigervnc/commit/b4ada8d0c6dac98c8b91fc64d112569a8ae5fb95