The X PixMap image format is an extension of the monochrome X BitMap format specified in the X protocol, and is commonly used in traditional X applications.
An integer overflow was discovered in libXpm’s src/CrDatFrI.c file. On 64 bit systems, this allows an overflow to occur on 32 bit integers while parsing XPM extensions in a file.
A remote attacker, by enticing a user to process a specially crafted XPM file, could execute arbitrary code with the privileges of the process or cause a Denial of Service condition.
There is no known workaround at this time.
All libXpm users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=x11-libs/libXpm-3.5.12"