CVE-2025-21590
Junos OS: An local attacker with shell access can execute arbitrary code
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
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.
Official description from the CVE record, published by juniper. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 4.0 Medium 6.7
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Attack vector: Local
The attacker needs local access to the system, or to trick a user into running something.
Attack complexity: Low
No measurable action is needed to get around the system's built-in security controls. The attack is repeatable.
Attack requirements: None
The attack works without any special deployment or execution conditions.
Privileges required: High
An account with significant privileges, such as an administrator, is needed.
User interaction: None
No action from any user is needed.
Vulnerable system: confidentiality: None
No effect on the secrecy of data.
Vulnerable system: integrity: High
Serious or total effect on the trustworthiness of data.
Vulnerable system: availability: None
No effect on availability.
Subsequent systems: confidentiality: None
No effect on other systems' data secrecy.
Subsequent systems: integrity: None
No effect on other systems' data trustworthiness.
Subsequent systems: availability: None
No effect on other systems' availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Local | The attacker needs local access to the system, or to trick a user into running something. |
| Attack complexity | Low | No measurable action is needed to get around the system's built-in security controls. The attack is repeatable. |
| Attack requirements | None | The attack works without any special deployment or execution conditions. |
| Privileges required | High | An account with significant privileges, such as an administrator, is needed. |
| User interaction | None | No action from any user is needed. |
| Vulnerable system: confidentiality | None | No effect on the secrecy of data. |
| Vulnerable system: integrity | High | Serious or total effect on the trustworthiness of data. |
| Vulnerable system: availability | None | No effect on availability. |
| Subsequent systems: confidentiality | None | No effect on other systems' data secrecy. |
| Subsequent systems: integrity | None | No effect on other systems' data trustworthiness. |
| Subsequent systems: availability | None | No effect on other systems' availability. |
CVSS 3.1 Medium 4.4
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Attack vector: Local
The attacker needs local access to the system, or to trick a user into running something.
Attack complexity: Low
No special conditions are needed. The attack can be repeated at will.
Privileges required: High
An account with significant privileges, such as an administrator, is needed.
User interaction: None
No action from any user is needed.
Scope: Unchanged
The impact stays within the vulnerable component.
Confidentiality impact: None
No effect on the secrecy of data.
Integrity impact: High
Serious or total effect on the trustworthiness of data.
Availability impact: None
No effect on availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Local | The attacker needs local access to the system, or to trick a user into running something. |
| Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. |
| Privileges required | High | An account with significant privileges, such as an administrator, is needed. |
| User interaction | None | No action from any user is needed. |
| Scope | Unchanged | The impact stays within the vulnerable component. |
| Confidentiality impact | None | No effect on the secrecy of data. |
| Integrity impact | High | Serious or total effect on the trustworthiness of data. |
| Availability impact | None | No effect on availability. |
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EPSS
- Score
- 0.01749 (1.7% probability)
- Percentile
- 78.0%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
CISA Known Exploited Vulnerabilities
- Name in the catalog
- Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability
- Added to the catalog
- Mar 13, 2025
- Federal due date
- Apr 3, 2025
CISA assessment as of Mar 14, 2025
- Exploitation
- Recorded by CISA as active
- Automatable
- no
- Technical impact
- total
Weakness (CWE)
- CWE-653Improper Isolation or Compartmentalization
Affected products
Juniper Networks Junos OS
- affected: before 21.2R3-S9
- affected: 21.4 up to before 21.4R3-S10
- affected: 22.2 up to before 22.2R3-S6
- affected: 22.4 up to before 22.4R3-S6
- affected: 23.2 up to before 23.2R2-S3
- affected: 23.4 up to before 23.4R2-S4
- affected: 24.2 up to before 24.2R1-S2, 24.2R2
References
- supportportal.juniper.net/JSA93446vendor-advisory
- cloud.google.com/blog/topics/threat-intelligence/china-nexu…third-party-advisory
Timeline
- ID reserved
- Record published
- Added to CISA KEV
- Record last updated
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About CubePath
Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:18 UTC. Sources and licenses