There is a heap-based buffer over-read in the Exiv2::Internal::PngChunk::keyTXTChunk function of pngchunk_int.cpp in Exiv2 0.26. A crafted PNG file will lead to a remote denial of service attack.
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2017-17669.json"