PDFlib is a library providing functions to handle PDF files. It includes a modified TIFF library used to process TIFF images.
The TIFF library is subject to several known vulnerabilities (see GLSA 200410-11). Most of these overflows also apply to PDFlib.
A remote attacker could entice a user or web application to process a carefully crafted PDF file or TIFF image using a PDFlib-powered program. This can potentially lead to the execution of arbitrary code with the rights of the program processing the file.
There is no known workaround at this time.
All PDFlib users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=media-libs/pdflib-5.0.4_p1"