Cisco IOS 12.0 through 12.4 allows remote attackers to cause a denial of service (device crash) via (1) "abnormal" MGCP messages, aka CSCsd81407; and (2) a large facsimile packet, aka CSCej20505.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.016
EPSS Ranking 81.0%