libgadu before 1.11.4 and 1.12.0 before 1.12.0-rc3, as used in Pidgin and other products, allows remote Gadu-Gadu file relay servers to cause a denial of service (memory overwrite) or possibly execute arbitrary code via a crafted message.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.