ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2025-21590

Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability

Published Mar 12, 2025 · catalog updated Oct 1, 2026 · Juniper Junos OS

Patch now

CVE-2025-21590 is in the CISA known-exploited catalog, due Apr 3, 2025. Confirm Juniper Junos OS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Medium6.7
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
1.74%
Remediation
Remediation guidance
Affected products
cpe juniper/junos · vendor Juniper Junos OS

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe juniper/junos21.2
  • vendor Juniper Junos OSversion unspecified

How to fix CVE-2025-21590

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-21590 is in the CISA known-exploited catalog, due Apr 3, 2025. Confirm Juniper Junos OS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with 21.2. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-653. EPSS 1.74%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 12, 2025 · Catalog

    Detected

    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

  2. Mar 13, 2025 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  3. Apr 3, 2025 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  4. Oct 1, 2026 · Catalog

    Updated

    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

Sources

  • CISA KEVConfirmed exploitationCVE-2025-21590

    Juniper Junos OS contains an improper isolation or compartmentalization vulnerability. This vulnerability could allows a local attacker with high privileges to inject arbitrary code.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2025-21590

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-21590

    30-day exploitation probability 1.7%

    first.org
  • NIST NVDVulnerability recordCVE-2025-21590

    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 com

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2025-21590

    Juniper Junos OS contains an improper isolation or compartmentalization vulnerability. This vulnerability could allows a local attacker with high privileges to inject arbitrary code.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.