An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).When processing a high rate of specific GRE traffic destined to the device, the respective PFE will hang causing traffic forwarding to stop. 



When this issue occurs the following logs can be observed:

 <fpc #> MQSS(0): LI-3: Received a parcel with more than 512B accompanying data 
CHASSISD_FPC_ASIC_ERROR: ASIC Error detected <...>


This issue affects Junos OS:

  *  all versions before 21.2R3-S9,
  *  21.4 versions before 21.4R3-S8,
  *  22.2 versions before 22.2R3-S4,
  *  22.4 versions before 22.4R3-S5,
  *  23.2 versions before 23.2R2-S2,
  *  23.4 versions before 23.4R2.

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE-754

https://supportportal.juniper.net/JSA96471