Junos OS: SRX Series: Under a specific device configuration an attacker can access the devices J-Web management services from any interface, regardless of security settings protecting the service

published 2021-10-19 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18294

cvss: 7.2; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits: 0; none known

Due to a Missing Authorization weakness and Insufficient Granularity of Access Control in a specific device configuration, a vulnerability exists in Juniper Networks Junos OS on SRX Series whereby an attacker who attempts to access J-Web administrative interfaces can successfully do so from any device interface regardless of the web-management configuration and filter rules which may otherwise protect access to J-Web. This issue affects: Juniper Networks Junos OS SRX Series 20.4 version 20.4R1 and later versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.

Patch / fix

fixed in 1

Juniper Networks Junos OS 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2

Exploit prediction

1.16% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.2	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
NVD	3.1	10.0	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

Juniper Networks Junos OS

Classification

Weakness

CWE-285 Improper Authorization
CWE-862 Missing Authorization
CWE-551 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
CWE-939 Improper Authorization in Handler for Custom URL Scheme
CWE-1220 Insufficient Granularity of Access Control

References

kb.juniper.net /InfoCenter/index?page=content&id=JSA11252
vendor-advisory
kb.juniper.net /
permissions-required

Sources

CVE List CVE-2021-31384
NVD CVE-2021-31384

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Summary