{"id":"CVE-2026-21902","published":"2026-02-25T16:59:10Z","modified":"2026-03-04T04:55:12Z","title":"Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root","vendor":"Juniper Networks","product":"Junos OS Evolved","tier":"core","eol":null,"affectedVersions":[{"vendor":"Juniper Networks","product":"Junos OS Evolved","versions":[">= 25.4, < 25.4R1-S1-EVO, 25.4R2-EVO"]}],"description":{"text":"An Incorrect Permission Assignment for Critical Resource vulnerability in the On-Box Anomaly detection framework of Juniper Networks Junos OS Evolved on PTX Series allows an unauthenticated, network-based attacker to execute code as root.\n\nThe On-Box Anomaly detection framework should only be reachable by other internal processes over the internal routing instance, but not over an externally exposed port. With the ability to access and manipulate the service to execute code as root a remote attacker can take complete control of the device.\nPlease note that this service is enabled by default as no specific configuration is required.\n\nThis issue affects Junos OS Evolved on PTX Series:\n\n\n\n  *  25.4 versions before 25.4R1-S1-EVO, 25.4R2-EVO.\n\n\n\n\nThis issue does not affect Junos OS Evolved versions before 25.4R1-EVO.\n\nThis issue does not affect Junos OS.","provenance":"source","from":"CVE.org"},"summary":{"text":"A critical-resource permission flaw in the On-Box Anomaly detection framework of Juniper Networks Junos OS Evolved on PTX Series routers, which is meant to be reachable only by internal processes over the internal routing instance but is exposed on an external port and enabled by default. An unauthenticated attacker with network access can reach the service and execute code as root, gaining full control of the device, with no authentication or user interaction required and no special configuration needed.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T08:32:11Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.18476,"percentile":0.97243,"date":"2026-10-31","provenance":"source"},"kev":null,"vulncheckKev":{"dateAdded":"2026-03-14","exploitedFirstSeen":"2026-03-14","ransomware":false,"evidence":[{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-14&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-14"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-17&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-17"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-18&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-18"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-19&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-19"},{"url":"https://www.dataminr.com/resources/intel-brief/cve-2026-21902-juniper-devices/","date":"2026-03-19"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-20&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-20"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-24&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-24"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-28&host_type=src&vulnerability=cve-2026-21902","date":"2026-03-28"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-04-06&host_type=src&vulnerability=cve-2026-21902","date":"2026-04-06"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-04-12&host_type=src&vulnerability=cve-2026-21902","date":"2026-04-12"}],"evidenceTotal":17,"provenance":"source"},"exploited":true,"otx":null,"cwes":[{"id":"CWE-732","name":"Incorrect Permission Assignment for Critical Resource"}],"references":[{"url":"https://supportportal.juniper.net/JSA107128","tags":["vendor-advisory"]},{"url":"https://kb.juniper.net/JSA107128","tags":["vendor-advisory"]},{"url":"https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902/blob/main/watchTowr-vs-JunosEvolved-CVE-2026-21902.py","tags":["exploit"]}],"techniques":[],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-8693","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-8693","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":0,"earliest":"2026-02-28","earliestUrl":"https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902","repos":[{"name":"watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902","url":"https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902","stars":4,"created":"2026-02-28"}]},"first":{"date":"2026-02-28","source":"PoC-in-GitHub","url":"https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902"},"provenance":"source"},"exploitRefs":["https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902/blob/main/watchTowr-vs-JunosEvolved-CVE-2026-21902.py"],"flow":[],"timeline":[{"date":"2026-02-25","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2026-21902","provenance":"source"},{"date":"2026-02-28","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/watchtowrlabs/watchTowr-vs-JunosEvolved-CVE-2026-21902","provenance":"source"},{"date":"2026-03-14","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-14&host_type=src&vulnerability=cve-2026-21902","provenance":"source"}],"speed":{"daysToPublicExploit":3,"firstExploitFrom":"PoC-in-GitHub","daysToKev":null},"priority":{"score":71.3,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in VulnCheck KEV"},{"name":"Recent KEV listing","points":5.0,"detail":"added 232 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.45,"detail":"percentile 0.9724"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 1 PoC-in-GitHub repo"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}