German software developer Hanno B..ck has discovered a bug in popular PDF viewer apps. The bug was discovered in 2011 by Andreas Bogk, a fellow German developer. Bogk discovered that PDF documents with a certain structure would cause the Evince app to enter a continuous loop that would take up all of the local CPU’s resources, and quickly run out of memory, crashing the app. The error bug was mostly ignored since it was never deemed a major security issue and only affected a small Linux app installed only on Linux.
Source: https://www.bleepingcomputer.com/news/software/six-year-old-loop-bug-re-discovered-to-affect-almost-all-major-pdf-viewers/