Junos OS: MX Series: In specific DHCPv6 scenarios jdhcpd memory increases continuously with subscriber logouts

A Missing Release of Memory after Effective Lifetime vulnerability in the DHCP daemon (jdhcpd) of Juniper Networks Junos OS on MX Series, allows an adjacent, unauthenticated attacker to cause a memory leak, that will eventually cause a complete Denial-of-Service (DoS).

In a DHCPv6 over PPPoE, or DHCPv6 over VLAN with Active lease query or Bulk lease query scenario, every subscriber logout will leak a small amount of memory. When all available memory has been exhausted, jdhcpd will crash and restart which causes a complete service impact until the process has recovered.

The memory usage of jdhcpd can be monitored with:

user@host> show system processes extensive | match jdhcpd

This issue affects Junos OS:

* all versions before 22.4R3-S1,
* 23.2 versions before 23.2R2,
* 23.4 versions before 23.4R2.