CVE-2023-36851: Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

CISA Known Exploited Vulnerabilities

Name

Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

Vendor

Juniper

Product

Junos OS

Added to the catalog

2023-11-13

Due date for US federal agencies

2023-11-17

Weaknesses

CWE-306

Catalog version

2026.10.30

Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity. With a specific request to webauth_operation.php that doesn't require authentication, an attacker is able to upload arbitrary files via J-Web, leading to a loss of integrity for a certain part of the file system, which may allow chaining to other vulnerabilities.

Required action (CISA)

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://supportportal.juniper.net/s/article/2023-08-Out-of-Cycle-Security-Bulletin-Junos-OS-SRX-Series-and-EX-Series-Multiple-vulnerabilities-in-J-Web-can-be-combined-to-allow-a-preAuth-Remote-Code-Execution?language=en_US
• https://nvd.nist.gov/vuln/detail/CVE-2023-36851

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2023-09-27T15:18:54.877

Last modified

2026-06-17T06:07:13.967

Weaknesses

CWE-306

A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity.



With a specific request to

webauth_operation.php

that doesn't require authentication, an attacker is able to upload and download arbitrary files via J-Web, leading to a loss of

integrity or confidentiality, which may allow chaining to other vulnerabilities.


This issue affects Juniper Networks Junos OS on SRX Series:



*

21.2 versions prior to 21.2R3-S8;
* 21.4

versions prior to

21.4R3-S6;
* 22.1

versions prior to

22.1R3-S5;
* 22.2

versions prior to

22.2R3-S3;
* 22.3

versions prior to

22.3R3-S2;
* 22.4 versions prior to 22,4R2-S2, 22.4R3;
* 23.2 versions prior to

23.2R1-S2, 23.2R2.

References

• https://supportportal.juniper.net/JSA72300 (Vendor Advisory)
• https://supportportal.juniper.net/JSA72300 (Vendor Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-36851 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:08.214Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2023-36851

CVE record

Title (CNA)

Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files

Assigner

juniper

State

PUBLISHED

Published

2023-09-26T19:53:17.080Z

Updated

2025-10-21T23:05:36.801Z

Problem types

CWE-306 Missing Authentication for Critical Function

A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity.



With a specific request to

webauth_operation.php

that doesn't require authentication, an attacker is able to upload and download arbitrary files via J-Web, leading to a loss of

integrity or confidentiality, which may allow chaining to other vulnerabilities.


This issue affects Juniper Networks Junos OS on SRX Series:



*

21.2 versions prior to 21.2R3-S8;
* 21.4

versions prior to

21.4R3-S6;
* 22.1

versions prior to

22.1R3-S5;
* 22.2

versions prior to

22.2R3-S3;
* 22.3

versions prior to

22.3R3-S2;
* 22.4 versions prior to 22,4R2-S2, 22.4R3;
* 23.2 versions prior to

23.2R1-S2, 23.2R2.

References

• https://supportportal.juniper.net/JSA72300

Read on 2026-11-03T02:04:07.231Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2023/36xxx/CVE-2023-36851.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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