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.
Advisories

No advisories yet.

Fixes

Solution

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.


Workaround

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

History

Thu, 15 Jan 2026 20:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Junos OS: SRX Series: With GRE performance acceleration enabled, receipt of a specific ICMP packet causes the PFE to crash
Weaknesses CWE-755
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Red'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: juniper

Published:

Updated: 2026-01-15T20:20:32.530Z

Reserved: 2026-01-05T17:32:48.710Z

Link: CVE-2026-21906

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-01-15T21:16:06.177

Modified: 2026-01-15T21:16:06.177

Link: CVE-2026-21906

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses