The networkstatus_parse_vote_from_string function in routerparse.c in Tor before 0.2.2.38 does not properly handle an invalid flavor name, which allows remote attackers to cause a denial of service (out-of-bounds read and daemon crash) via a crafted (1) vote document or (2) consensus document.
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.