IRONSMITHINTEL
MEDIUMCVSS5.3
|
Actively Exploited
|CISA KEV|CVE-2023-36847|Auth: none — unauthenticated|Reboot: required|Manual only

Juniper Junos OS EX Series Missing Authentication for Critical Function Vulnerability (CVE-2023-36847)

Juniper Junos OS on EX 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 installAppPackage.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.

Published Aug 17, 2023 · Updated May 17, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve partial data exposure, partial data tampering. Federal agencies are required to remediate by 2023-11-17 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Missing Authentication for Critical Function (CWE-306) vulnerability in Juniper Junos OS. A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on EX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity. With a specific request to installAppPackage.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. This issue affects Juniper Networks Junos OS on EX Series: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S4; * 22.1 versions prior to 22.1R3-S3; * 22.2 versions prior to 22.2R3-S1; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2-S1, 22.4R3. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

Network Security Team
Firewall Administrators
IT Security
Running junos: v < 20.4, 20.4, 21.1, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, 22.4
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2023-11-13 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2023-11-17.

How to patch

Manual remediation steps

1
Identify affected hosts: query inventory for network-security installs in scope.
2
Apply the vendor security update referenced in CVE-2023-36847's advisory. No specific KB/version is encoded yet — consult the linked MSRC/vendor URL.
3
Verify the fix per the vendor's published verification steps.
4
Document the remediation in your change ticket and re-scan with your vulnerability scanner to confirm closure.
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