CVE-2021-31384Network attack vector

Management-interface exposure via unenforced J-Web restrictions

Published Oct 19, 2021 · Updated Sep 16, 2024

Missing authorization in J-Web on Junos OS SRX Series allows remote attackers to reach administration from unintended interfaces. When HTTP or HTTPS web management is enabled, interface restrictions and filter rules are not enforced before J-Web accepts requests. The flaw exposes management access from any device interface despite configured restrictions; Juniper has not published a lower-level code locus.

CVSS severity7.2
High
EPSS probability1.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in J-Web on Junos OS SRX Series allows remote attackers to reach administration from unintended interfaces. When HTTP or HTTPS web management is enabled, interface restrictions and filter rules are not enforced before J-Web accepts requests. The flaw exposes management access from any device interface despite configured restrictions; Juniper has not published a lower-level code locus.

The record

CVE
CVE-2021-31384
Published
Oct 19, 2021
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-285, CWE-1220, CWE-862, CWE-939, CWE-551, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=20.4R1 <20.4* changes=[{"at":"20.4R2-S1, 20.4R3","status":"unaffected"}]
  2. Affected versionversion=21.1 <21.1R1-S1, 21.1R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=20.4R1 <20.4* changes=[{"at":"20.4R2-S1, 20.4R3","status":"unaffected"}]; version=21.1 <21.1R1-S1, 21.1R2

Published CVSS scores

7.2Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
10.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-1220Insufficient Granularity of Access Control
CWE-862Missing Authorization
CWE-939Improper Authorization in Handler for Custom URL Scheme
CWE-551Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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