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Known exploited vulnerability

CVE-2025-21590

mediumCVSS 4.0 6.7In CISA KEVEPSS 1.7%Published · Juniper Networks

The short answer

CVE-2025-21590 affects Juniper Networks Junos OS and is rated medium (CVSS 6.7). CISA added it to the Known Exploited Vulnerabilities catalog on 2025-03-13: attackers are using it, so patch it first.

What it is

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.

Weakness: CWE-653.

Severity

6.7 medium

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Exploited (CISA KEV)

Yes, since Mar 13, 2025

Federal due date Apr 3, 2025

EPSS, next 30 days

1.7%

Higher than 78% of scored CVEs

How it can be exploited

Attack vector
Local
Attack complexity
Low
Attack requirements
None
Privileges required
High
User interaction
None
Confidentiality impact
None
Integrity impact
High
Availability impact
None

What CISA says to do

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

Affected products

Junos OS. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2025-21590 being exploited?

Yes. CISA added CVE-2025-21590 to its Known Exploited Vulnerabilities catalog on 2025-03-13, with a federal remediation due date of 2025-04-03.

How do I fix CVE-2025-21590?

CISA's 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.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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