CVE-2021-31384

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

CRITICAL
10
CVSS Score
Published: October 19, 2021 at 06:17 PM UTC
Updated: June 17, 2026 at 03:51 AM UTC
10 products affected across 2 vendorsJunosSRX5600SRX5800

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Severity
CRITICAL10
Exploit prediction
EPSS 1%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

20.4R1 ≤ v < 20.4*21.1 ≤ v < 21.1R1-S1, 21.1R220.4 r120.4 r1-s120.4 r220.4R121.121.1 r1
Affected range stops below 20.4*, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 20.4R1 (unaffected)
Affected range stops below 21.1R1-S1, 21.1R2, so it looks safe — our inference, not a vendor statement
juniper-srx1500 (environment) · juniper-srx300 (environment) · juniper-srx4100 (environment) · juniper-srx4200 (environment) · juniper-srx4600 (environment) · juniper-srx5400 (environment) · juniper-srx550 (environment) · juniper-srx5600 (environment) · juniper-srx5800 (environment)
All versions
All versions
All versions
All versions
All versions
All versions
All versions
All versions
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-285CWE-551CWE-862CWE-939CWE-1220

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