Vulnerability details

CVE-2026-21906

Juniper Networks Junos OS

Junos OS: SRX Series: With GRE performance acceleration enabled, receipt of a specific ICMP packet causes the PFE to crash

CVSS 4.0
8.7High

Official 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.

CVSS scores

ScoreVersionSourceVector
8.7High 4.0 CVEProject cvelistV5 (CNA) (juniper) 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
7.5High 3.1 CVEProject cvelistV5 (CNA) (juniper) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

VendorProductVersionsSource
Juniper Networks Junos OS v < 21.4R3-S12 CVEProject cvelistV5 (CNA)
Juniper Networks Junos OS 22.4 ≤ v < 22.4R3-S8 CVEProject cvelistV5 (CNA)
Juniper Networks Junos OS 23.2 ≤ v < 23.2R2-S5 CVEProject cvelistV5 (CNA)
Juniper Networks Junos OS 23.4 ≤ v < 23.4R2-S5 CVEProject cvelistV5 (CNA)
Juniper Networks Junos OS 24.2 ≤ v < 24.2R2-S3 CVEProject cvelistV5 (CNA)
Juniper Networks Junos OS 24.4 ≤ v < 24.4R2-S1 CVEProject cvelistV5 (CNA)
Juniper Networks Junos OS 25.2 ≤ v < 25.2R1-S1, 25.2R2 CVEProject cvelistV5 (CNA)

References and advisories

3
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Details

Published
2026-01-15
Last updated
2026-01-16
State
Published
Assigner (CNA)
juniper

Exploit prediction (EPSS)

0.54%
Probability of exploitation in 30 days
45.6%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Partial

Weaknesses (CWE)

  • CWE-755
    Improper Handling of Exceptional Conditions