In Xpdf 4.05 (and earlier), invalid header info in a DCT (JPEG) stream can lead to an uninitialized variable in the DCT decoder. The proof-of-concept PDF file causes a segfault attempting to read from an invalid address.
Out-of-bounds array write in Xpdf 4.05 and earlier, triggered by an invalid character code in a Type 1 font. The root problem was a bounds check that was being optimized away by modern compilers.