Buffer Access Vulnerability in Juniper Networks Junos OS DHCP Daemon

CVE-2025-21591

What is CVE-2025-21591?

A buffer access vulnerability exists in the jdhcpd daemon of Juniper Networks Junos OS, triggered when DHCP snooping is enabled. An adjacent, unauthenticated attacker can exploit this flaw by sending a malformed DHCP packet, causing the jdhcp process to crash and resulting in a Denial of Service (DoS) condition. Sustained delivery of these malformed packets can lead to an extended service outage. This issue impacts specific versions of Junos OS while leaving earlier versions unaffected, and does not affect the vSRX Series or Junos OS Evolved.

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