Improper handling of exceptional conditions in Junos OS - CVE-2026-21906
Published: January 19, 2026
Vulnerability identifier: #VU121663
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-21906
CWE-ID: CWE-755
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to improper handling of exceptional conditions error in the packet forwarding engine (PFE) when PowerMode IPsec (PMI) and GRE performance acceleration are enabled. A remote non-authenticated attacker can cause the PFE to crash and restart by sending specially crafted ICMP packets.
Affected software
Junos OS
How to mitigate CVE-2026-21906
Install updates from vendor's website.
Junos OS - addressed in versions 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