An Improper Check for Unusual or Exceptional Conditions vulnerability in Juniper DHCP Daemon (jdhcpd) of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause the jdhcpd to consume all the CPU cycles resulting in a Denial of Service (DoS).

On Junos OS devices with forward-snooped-client configured, if an attacker sends a specific DHCP packet to a non-configured interface, this will cause an infinite loop. The DHCP process will have to be restarted to recover the service.

This issue affects:

Juniper Networks Junos OS

• All versions earlier than 20.4R3-S9;
• 21.2 versions earlier than 21.2R3-S7;
• 21.3 versions earlier than 21.3R3-S5;
• 21.4 versions earlier than 21.4R3-S5;
• 22.1 versions earlier than 22.1R3-S4;
• 22.2 versions earlier than 22.2R3-S3;
• 22.3 versions earlier than 22.3R3-S2;
• 22.4 versions earlier than 22.4R2-S2, 22.4R3;
• 23.2 versions earlier than 23.2R2.

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-36842
• https://supportportal.juniper.net/JSA75730
• https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N