Use-after-free in Junos OS Evolved and Juniper Junos OS - CVE-2026-21908
Published: January 20, 2026
Vulnerability identifier: #VU121702
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-21908
CWE-ID: CWE-416
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vendor: Juniper Networks, Inc.
Affected software:
Junos OS Evolved
Juniper Junos OS
Junos OS Evolved
Juniper Junos OS
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to a use-after-free error in the 802.1X authentication daemon (dot1xd). A remote authenticated user can execute arbitrary code with elevated privileges.
This issue affects systems with 802.1X authentication port-based network access control (PNAC) enabled.
How to mitigate CVE-2026-21908
Install updates from vendor's website.