VYPR
Unrated severityNVD Advisory· Published Jan 15, 2026· Updated Jan 16, 2026

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

CVE-2026-21906

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.

Affected products

2
  • Range: (<21.4R3-S12) or (≥22.4 and <22.4R3-S8) or (≥23.2 and <23.2R2-S5) or (≥23.4 and <23.4R2-S5) or (≥24.2 and <24.2R2-S3) or (≥24.4 and <24.4R2-S1) or (≥25.2 and <25.2R1-S1) or (=25.2R2)
  • Juniper Networks/Junos OSv5
    Range: 0

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

3

News mentions

0

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