Improper Check for Unusual or Exceptional Conditions in Junos OS - CVE-2026-21910
Published: January 20, 2026
Vulnerability identifier: #VU121701
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-21910
CWE-ID: CWE-754
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to improper check for unusual or exceptional conditions error in the packet forwarding engine (PFE). A remote non-authenticated attacker can cause traffic between VXLAN Network Identifiers (VNIs) to drop, leading to a Denial of Service (DoS).
Affected software
Junos OS
How to mitigate CVE-2026-21910
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, 25.2R1