The Instance::HandleInputEvent function in pdf/instance.cc in the PDFium component in Google Chrome before 38.0.2125.101 interprets a certain -1 value as an index instead of a no-visible-page error code, which allows remote attackers to cause a denial of service (out-of-bounds read) via unspecified vectors.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.