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.
Exploitability
AV:LAC:LPR:NUI:RScope
S:UImpact
C:NI:NA:H5.5/CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H