aspell is a popular spell-checker. Dictionaries are available for many languages.
aspell includes a utility for handling wordlists called word-list-compress. This utility fails to do proper bounds checking when processing words longer than 256 bytes.
If an attacker could entice a user to handle a wordlist containing very long word lengths it could result in the execution of arbitrary code with the permissions of the user running the program.
There is no known workaround at this time. All users are encouraged to upgrade to the latest available version.
All users should upgrade to the latest available version of aspell.
# emerge sync
# emerge -pv ">=app-text/aspell-0.50.5-r4"
# emerge ">=app-text/aspell-0.50.5-r4"