An Improper Handling of Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an unauthenticated network-based attacker sending a specific ICMP packet through a GRE tunnel to cause the PFE to crash and restart.

When PowerMode IPsec (PMI) and GRE performance acceleration are enabled and the device receives a specific ICMP packet, a crash occurs in the SRX PFE, resulting in traffic loss. PMI is enabled by default, and GRE performance acceleration can be enabled by running the configuration command shown below. PMI is a mode of operation that provides IPsec performance improvements using Vector Packet Processing.

Note that PMI with GRE performance acceleration is only supported on specific SRX platforms.

This issue affects Junos OS on the SRX Series:

• all versions before 21.4R3-S12, 
• from 22.4 before 22.4R3-S8, 
• from 23.2 before 23.2R2-S5, 
• from 23.4 before 23.4R2-S5, 
• from 24.2 before 24.2R2-S3, 
• from 24.4 before 24.4R2-S1, 
• from 25.2 before 25.2R1-S1, 25.2R2.

This issue requires GRE performance acceleration to be enabled:

[set security flow gre-performance-acceleration]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

The following software releases have been updated to resolve this specific issue: Junos OS 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S5, 24.2R2-S3, 24.4R2-S1, 25.2R1-S1, 25.2R2, 25.4R1, and all subsequent releases.

This issue is being tracked as 1868005 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

• Disable GRE performance acceleration via 'deactivate security flow gre-performance-acceleration'
  or
• Disable PMI via 'set security flow power-mode-disable'

2026-01-14: Initial Publication

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team