Multiple integer overflows in pktlength.c in Chrony before 1.29 allow remote attackers to cause a denial of service (crash) via a crafted (1) REQ_SUBNETS_ACCESSED or (2) REQ_CLIENT_ACCESSES command request to the PKL_CommandLength function or crafted (3) RPY_SUBNETS_ACCESSED, (4) RPY_CLIENT_ACCESSES, (5) RPY_CLIENT_ACCESSES_BY_INDEX, or (6) RPY_MANUAL_LIST command reply to the PKL_ReplyLength function, which triggers an out-of-bounds read or buffer overflow. NOTE: versions 1.27 and 1.28 do not require authentication to exploit.

cmdmon.c in Chrony before 1.29 allows remote attackers to obtain potentially sensitive information from stack memory via vectors related to (1) an invalid subnet in a RPY_SUBNETS_ACCESSED command to the handle_subnets_accessed function or (2) a RPY_CLIENT_ACCESSES command to the handle_client_accesses function when client logging is disabled, which causes uninitialized data to be included in a reply.

The read_from_cmd_socket function in cmdmon.c in chronyd in Chrony before 1.23.1, and 1.24-pre1, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by sending a spoofed cmdmon packet that triggers a continuous exchange of NOHOSTACCESS messages between two daemons, a related issue to CVE-2009-3563.

chronyd in Chrony before 1.23.1, and possibly 1.24-pre1, generates a syslog message for each unauthorized cmdmon packet, which allows remote attackers to cause a denial of service (disk consumption) via a large number of invalid packets.

The client logging functionality in chronyd in Chrony before 1.23.1 does not restrict the amount of memory used for storage of client information, which allows remote attackers to cause a denial of service (memory consumption) via spoofed (1) NTP or (2) cmdmon packets.