libTIFF provides support for reading and manipulating TIFF (Tagged Image File Format) images.
Drew Yao (Apple Product Security) and Clay Wood reported multiple buffer underflows in the LZWDecode() and LZWDecodeCompat() functions in tif_lzw.c when processing TIFF files.
A remote attacker could entice a user to open a specially crafted TIFF file with an application making use of libTIFF, possibly resulting in the remote execution of arbitrary code with the privileges of the user running the application.
There is no known workaround at this time.
All libTIFF users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=media-libs/tiff-3.8.2-r4"