CVE-2025-21590: Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability
Affects Juniper Junos OSSource CISA KEV
Exploited in the wild · KEV due 3 Apr 2025 · 1% EPSS : apply the vendor's fix or mitigations to Juniper Junos OS now.
Data as of 10/24/2026, 22:16:00 UTC
- Exploitation
Actively exploited – in CISA KEV since 03/13/2025
- KEV deadline
- 04/03/2025 US federal agencies must patch by this date; a sensible deadline for everyone else.
- EPSS
- 1.7% chance of exploitation in 30 days – higher than 77% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:NWhat to do
CISA required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Check the firmware or software version for Juniper Junos OS in the device's admin interface against the vendor advisory.
Description
Juniper Junos OS contains an improper isolation or compartmentalization vulnerability. This vulnerability could allows a local attacker with high privileges to inject arbitrary code.
Weaknesses
- CWE-653Improper Isolation or Compartmentalization (opens in a new tab)
Class weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.
References
- supportportal.juniper.net/s/article/2025-03-Out-of-Cycle-Security-Bulletin-Junos-OS-A-local-attacker-with-shell-access-can-execute-arbitrary-code-CVE-2025-21590?language=en_US (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2025-21590 (opens in a new tab)
- cisa.gov/known-exploited-vulnerabilities-catalog?search=CVE-2025-21590 (opens in a new tab)