CVE 2010-1324
MIT Kerberos 5 (aka krb5) 1.7.x and 1.8.x through 1.8.3 does not properly determine the acceptability of checksums, which might allow remote attackers to forge GSS tokens, gain privileges, or have unspecified other impact via (1) an unkeyed checksum, (2) an unkeyed PAC checksum, or (3) a KrbFastArmoredReq checksum based on an RC4 key.
See the
CVE page on Mitre.org
for more details.