What is CVE-2026-21902?
Critical pre-authentication remote code execution vulnerability in Juniper Networks PTX Series routers running Junos OS Evolved. The On-Box Anomaly Detection Framework's Python REST API binds to all interfaces (0.0.0.0:8160/TCP) instead of localhost, allowing unauthenticated attackers to execute arbitrary commands as root via crafted DAG workflow definitions.
The record classifies CVE-2026-21902 under weakness classes CWE-276, CWE-732. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 7 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 222 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS v4.0 base score
- 9.3
- EPSS (FIRST)
- 0.0% probability of exploitation in the next 30 days, higher than 26.8% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-02-25, last modified 2026-03-30
Is CVE-2026-21902 being exploited?
It currently carries a trending score of 12 in the Threadlinqs vulnerability feed.
Affected products and versions
- Juniper: Junos Os Evolved, Ptx10001-36Mr, Ptx10002-36Qdd, Ptx10003, Ptx10004, Ptx10008, Ptx10016
How to fix CVE-2026-21902
Vendor advisory: https://kb.juniper.net/JSA107128. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-21902
1 tracked threat in the Threadlinqs corpus references CVE-2026-21902, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Seeded from threat-derived and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.