An out-of-bounds read vulnerability exists in the way 7-Zip
handles Universal Disk Format (UDF) files.
Central to 7-Zip’s processing of UDF files is the
CInArchive::ReadFileItem method. Because volumes can have more than
one partition map, their objects are kept in an object vector. To
start looking for an item, this method tries to reference the proper
object using the partition map’s object vector and the "PartitionRef"
field from the Long Allocation Descriptor. Lack of checking whether
the "PartitionRef" field is bigger than the available amount of
partition map objects causes a read out-of-bounds and can lead, in
some circumstances, to arbitrary code execution.