{"id":"CVE-2025-21590","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-21590","generatedAt":"2026-10-31T08:11:47.785Z","title":"Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability","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.\n\nA local attacker with access to the shell is able to inject arbitrary code which can compromise an affected device.\nThis issue is not exploitable from the Junos CLI.\nThis issue affects Junos OS: \n\n\n\n  *  All versions before 21.2R3-S9,\n  *  21.4 versions before 21.4R3-S10, \n  *  22.2 versions before 22.2R3-S6, \n  *  22.4 versions before 22.4R3-S6, \n  *  23.2 versions before 23.2R2-S3, \n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R1-S2, 24.2R2.","published":"2025-03-12T14:15:15.000Z","lastModified":"2026-10-01T18:23:35.000Z","status":"Analyzed","sourceIdentifier":"sirt@juniper.net","cvss":{"version":"4.0","score":6.7,"severity":"MEDIUM","vector":"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/M"},"cwe":["CWE-653"],"affected":["juniper/junos"],"epss":{"score":0.01735,"percentile":0.7764,"date":"2026-10-30","history":[]},"kev":{"listed":true,"dateAdded":"2025-03-13","dueDate":"2025-04-03","knownRansomwareCampaignUse":"Unknown","notes":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.\nhttps://supportportal.juniper.net/s/article/2025-03-Out-of-Cycle-Security-Bulletin-Junos-OS-A-local-attacker-with-shell-access-can-execute-arbitrary-code-CVE-2025-21590?language=en_US ; https://nvd.nist.gov/vuln/detail/CVE-2025-21590"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 April 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"https://cloud.google.com/blog/topics/threat-intelligence/china-nexus-espionage-targets-juniper-routers","tags":["Third Party Advisory"],"source":"sirt@juniper.net"},{"url":"https://supportportal.juniper.net/JSA93446","tags":["Vendor Advisory"],"source":"sirt@juniper.net"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21590","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-21590","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}