CVE-2021-31384

Name: CVE-2021-31384
Creator: NVD / NIST
Published: 2021-10-19T19:15:11.373+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 10/10EPSS 1.12%

Last modified Jun 17, 2026

CVE-2021-31384 is a critical-severity vulnerability rated 10/10 on the CVSS scale. 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. EPSS estimates a 1.12% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

10/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

1.12%

62.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Juniper	Junos	20.4	R1
Juniper	Junos	21.1	R1

References

https://kb.juniper.net/Permissions Required
https://kb.juniper.net/InfoCenter/index?page=content&id=JSA11252Vendor Advisory
https://kb.juniper.net/Permissions Required

Timeline

Published: Oct 19, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31384?

How severe is CVE-2021-31384?

CVE-2021-31384 has a CVSS score of 10/10 (CRITICAL severity). The EPSS model estimates a 1.12% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31384?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31384?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST