The get_input_token function in the SPNEGO implementation in MIT Kerberos 5 (aka krb5) 1.5 through 1.6.3 allows remote attackers to cause a denial of service (daemon crash) and possibly obtain sensitive information via a crafted length value that triggers a buffer over-read.
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.