CVE-2025-21590: medium-severity vulnerability in Juniper Networks Junos OS
Junos OS: An local attacker with shell access can execute arbitrary code
Published · Updated
43Vexday Risk Score
Prioritize patching. It under exploitation confirmed by CISA.
ssvc Attendcvss 6.7epss 1.7%
from disclosure to weapon
Published on NVDMar 12
CISA KEV+1d
exploitation probability
1.7%top 23% of all CVEs
observed exploitation
yesCISA + VulnCheck
Action required by CISAfederal deadline: 2025-04-03
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
In short
A vulnerability in Junos OS allows someone with shell access to run malicious code and take control of the device. This is a serious risk for systems where unauthorized users might gain shell privileges.
Technical detail
An improper kernel compartmentalization vulnerability (CWE-653) in Juniper Junos OS enables local privilege escalation via arbitrary code injection through shell access. Pre-condition: attacker must already have shell-level access; the flaw does not affect Junos CLI access. Impact: complete device compromise with integrity violation.
Summary generated and translated by AI from the official description.
An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges to compromise the integrity of the device.
A local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device.
This issue is not exploitable from the Junos CLI.
This issue affects Junos OS:
* All versions before 21.2R3-S9,
* 21.4 versions before 21.4R3-S10,
* 22.2 versions before 22.2R3-S6,
* 22.4 versions before 22.4R3-S6,
* 23.2 versions before 23.2R2-S3,
* 23.4 versions before 23.4R2-S4,
* 24.2 versions before 24.2R1-S2, 24.2R2.