The xmlParseMisc function in parser.c in libxml2 before 2.9.3 allows context-dependent attackers to cause a denial of service (out-of-bounds heap read) via unspecified vectors related to incorrect entities boundaries and start tags.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.