A vulnerability was discovered in SPICE before version 0.14.1 where the generated code used for demarshalling messages lacked sufficient bounds checks. A malicious client or server, after authentication, could send specially crafted messages to its peer which would result in a crash or, potentially, other impacts.
The issue has been fixed by upstream by bailing out with an error if the pointer to the start of some message data is strictly greater than the pointer to the end of the message data.
For Debian 7 Wheezy, these problems have been fixed in version 0.11.0-1+deb7u5.
We recommend that you upgrade your spice packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/