there is a possible out-of-bounds read due to a heap buffer
This could lead to remote information disclosure with no additional execution privileges needed. However, user interaction is needed for exploitation.
For Debian 8 jessie, these problems have been fixed in version 1.3.0-3+deb8u1.
We recommend that you upgrade your flac packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/