Junos OS (SRX firewalls)
CVE-2026-21916: A low privileged user can escalate their privileges so that they can login as root
A UNIX Symbolic Link (Symlink) Following vulnerability in the CLI of Juniper Networks Junos OS allows a local, authenticated attacker with low privileges to escalate their privileges to root which will lead to a complete compromise of the system.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS 0 | 23.2R2-S7 or later |
| Junos OS 23.4 | 23.4R2-S6 or later |
| Junos OS 24.2 | 24.2R2-S3 or later |
| Junos OS 24.4 | 24.4R2-S2 or later |
| Junos OS 25.2 | 25.2R2 or later |
| Junos OS 25.4R1 | Not affected |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A UNIX Symbolic Link (Symlink) Following vulnerability in the CLI of Juniper Networks Junos OS allows a local, authenticated attacker with low privileges to escalate their privileges to root which will lead to a complete compromise of the system.
When after a user has performed a specific 'file link ...' CLI operation, another user commits (unrelated configuration changes), the first user can login as root.
This issue affects Junos OS: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S6, * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S2, * 25.2 versions before 25.2R2.
This issue does not affect versions 25.4R1 or later.
Workarounds
To prevent exploitation, use access controls to keep users from performing 'file link' operations.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.