bzip2 is a free and open source lossless data compression program.
The Oulu University discovered that bzip2 does not properly check offsets provided by the bzip2 file, leading to a buffer overread.
Remote attackers can entice a user or automated system to open a specially crafted file that triggers a buffer overread, causing a Denial of Service. libbz2 and programs linking against it are also affected.
There is no known workaround at this time.
All bzip2 users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-arch/bzip2-1.0.5"