A malicious bzip2 payload may produce a memory corruption resulting in a denial of service and/or remote code execution. Network services or command line utilities decompressing untrusted bzip2 payloads are affected.
Note that the exploitation of this bug relies on an undefined behavior that appears to be handled safely by current compilers.
The Haskell libraires are vulnerable when they are built using the bundled C library source code, which is the default in most cases.