BlackTreeCVE Intelligence
← Back to the CVE catalogue
Full vulnerability report · 2025
CVE-2025-21590High confidence

Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability

Juniper · Junos OS

6.7MediumCVSS 4.0
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2025-04-03 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Critical, raised 2 bands.upgradedsince 13 Mar 2025

Evidence used

  • CISA confirms exploitation in the wild.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 1.75% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Juniper Junos OS and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-6303

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 13 Mar 2025. Evidence sources: cisa_kev.
ENISA score
6.7 · CVSS 4.0
Advisory evidence
1 linked advisory record
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2025-04-03 as the remediation due date.

Patch available
01

What, why and how

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

What

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

Why

The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may execute code or commands in the affected security context.

What

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

Why

The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2025-03-13.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Improper Isolation or Compartmentalization → execute code or commands in the affected security context
Attack surface
Local
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-653 ↗

CWE-653: Improper Isolation or Compartmentalization. The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
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

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
Remote code executionCWE-653CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2025-6303Known-exploited evidence recorded

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 EUVD record ↗
BSI · German · WID-SEC-2025-0552Juniper JUNOS: Schwachstelle ermöglicht Codeausführung

Ein lokaler Angreifer kann eine Schwachstelle in Juniper JUNOS ausnutzen, um beliebigen Programmcode auszuführen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV25-142Juniper Networks security advisory (AV25-142)

On March 12, 2025, Juniper Networks published a security advisory to address a vulnerability in the following product: Juniper has received reports that CVE-2025-21590 has been exploited.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0206Vulnérabilité dans Juniper Networks Junos OS

Une vulnérabilité a été découverte dans Juniper Networks Junos OS. Elle permet à un attaquant de provoquer une exécution de code arbitraire.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2025-002401ジュニパーネットワークスの Junos OS における隔離または分類に関する脆弱性

ジュニパーネットワークスの Junos OS には、隔離または分類に関する脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6405美 CISA 발표 주요 Exploit 정보공유(Update. 2025-03-13)

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

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Junos OS: 23.2 < 23.2R2-S3, 24.2 < 24.2R1-S2, 24.2R2, 22.2 < 22.2R3-S6, 0 < 21.2R3-S9, 23.4 < 23.4R2-S4, 21.4 < 21.4R3-S10, 22.4 < 22.4R3-S6
Fixed
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 12 Mar 2025 · Last source change 26 Feb 2026, 19:09 UTC · CWE-653 · Improper Isolation or Compartmentalization

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-6303
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added remediation: supportportal.juniper.net/JSA93446.
    Before
    vendor advisory: supportportal.juniper.net/JSA93446
    After
    remediation: supportportal.juniper.net/JSA93446 · vendor advisory: supportportal.juniper.net/JSA93446
    sirt@juniper.net ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 21.2R3-S9; 21.4 < 21.4R3-S10; 22.2 < 22.2R3-S6; 22.4 < 22.4R3-S6; 23.2 < 23.2R2-S3; 23.4 < 23.4R2-S4; 24.2 < 24.2R1-S2, 24.2R2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Junos OS: < 21.2R3-S9, 21.4 < 21.4R3-S10, 22.2 < 22.2R3-S6, 22.4 < 22.4R3-S6, 23.2 < 23.2R2-S3, 23.4 < 23.4R2-S4, 24.2 < 24.2R1-S2, 24.2R2 · Fixed: The following software releases have been updated to resolve this specific issue: 21.2R3-S9, 21.4R3-S10, 22.2R3-S6, 22.4R3-S6, 23.2R2-S3, 23.4R2-S4, 24.2R1-S2, 24.2R2, 24.4R1, and all subsequent releases.; Please note that this issue is not fixed for all platforms in the releases specified in the solution section.; For the following products the fix is only available in these releases:; SRX300 Series 21.2R3-S9, 23.4R2-S5*, 24.4R1; SRX550HM 22.2R3-S7*; EX4300 Series 21.4R3-S11* (except EX4300-48MP which has fixes available as indicated in the solution); EX4600 21.4R3-S11* (except EX4650 which has fixes available as indicated in the solution); ACX1000, ACX1100, ACX2100, ACX2200, ACX4000,; ACX500 21.2R3-S9; MX104 21.2R3-S9; * Future Release
    CNA ↗
  3. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    sirt@juniper.net ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2025-6303↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-21590 · cve.blacktree.nl