--- title: "CVE-2025-21590: Junos OS: An local attacker with shell… | CubePath" description: "An Improper Isolation or Compartmentalization vulnerability in the kernel of Juniper Networks Junos OS allows a local attacker with high privileges…" language: en source: https://cubepath.com/security/cve/CVE-2025-21590 --- # CVE-2025-21590: Junos OS: An local attacker with shell… | CubePath ## 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](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-21590) ## Key data ### CVSS 4.0 Medium 6.7 Score published by juniper in the CVE record. 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 | 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 Score published by juniper in the CVE record. CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N | 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. | CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) . ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.01749 (1.7% probability) Percentile 78.0% Scores of Nov 10, 2026 Model v2026.06.15 ### CISA Known Exploited Vulnerabilities This CVE is listed in the CISA KEV catalog. 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 Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA. Exploitation Recorded by CISA as active Automatable no Technical impact total ### Weakness (CWE) CWE catalog version 5.0. CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license. - [CWE-653](https://cwe.mitre.org/data/definitions/653.html) Improper Isolation or Compartmentalization ## Affected products Products listed in the CVE record, as the CNA published them. - 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 Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [supportportal.juniper.net/JSA93446](https://supportportal.juniper.net/JSA93446) vendor-advisory - [cloud.google.com/blog/topics/threat-intelligence/china-nexu…](https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers) third-party-advisory ## Timeline 1. ID reserved Dec 26, 2024 2. Record published Mar 12, 2025 3. Added to CISA KEV Mar 13, 2025 4. Record last updated Feb 26, 2026 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) 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, 20:04 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)