An Improper Handling of Exceptional Conditions vulnerability in packet processing of Juniper Networks Junos OS on MX Series with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C lines cards, MX304 devices, and Juniper Networks Junos OS Evolved on PTX Series, allows an attacker sending malformed DHCP packets to cause ingress packet processing to stop, leading to a Denial of Service (DoS).  Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition.

This issue only occurs if DHCP snooping is enabled. See configuration below.

This issue can be detected using following commands. Their output will display the interface status going down:

user@device>show interfaces <if--x/x/x>
user@device>show log messages | match <if--x/x/x>
user@device>show log messages ==> will display the "[Error] Wedge-Detect : Host Loopback Wedge Detected: PFE: no," logs.

This issue affects:
Junos OS on

MX Series

with MPC10/MPC11/LC9600 line cards, EX9200 with EX9200-15C line cards, and MX304:

* All versions before 21.2R3-S7,
* from 21.4 before 21.4R3-S6,
* from 22.2 before 22.2R3-S3,
* all versions of 22.3,
* from 22.4 before 22.4R3,
* from 23.2 before 23.2R2;

Junos OS Evolved on PTX Series:
* from 19.3R1-EVO before 21.2R3-S8-EVO,

* from 21.4-EVO before 21.4R3-S7-EVO,
* from 22.1-EVO before 22.1R3-S6-EVO,
* from 22.2-EVO before 22.2R3-S5-EVO,
* from 22.3-EVO before 22.3R3-S3-EVO,
* from 22.4-EVO before 22.4R3-S1-EVO,
* from 23.2-EVO before 23.2R2-S2-EVO,
* from 23.4-EVO before 23.4R2-EVO.

Junos OS Evolved releases prior to 19.3R1-EVO are unaffected by this vulnerability