CVE-2023-36844

What it is

A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series allows an unauthenticated, network-based attacker to control certain, important environment variables. Using a crafted request an attacker is able to modify certain PHP environment variables leading to partial loss of integrity, which may allow chaining to other vulnerabilities. This issue affects Juniper Networks Junos OS on EX Series: * All versions prior to 20.4R3-S9; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S7; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R3-S1; * 22.4 versions prior to 22.4R2-S2, 22.4R3; * 23.2 versions prior to 23.2R1-S1, 23.2R2.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

In the wild

CISA lists this as exploited in real attacks. Treat as urgent.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-06-27 16:17 UTC ReservedThe CVE id was reserved by its CNA
2. 2023-08-17 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2023-11-13 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
4. 2023-11-17 Remediation deadlineCISA's due date for federal agencies to fix it
5. 2026-06-17 06:07 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
• Exploit odds: 90.0% in the next 30 days (EPSS).
• Severity: 5.3 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-08-17 20:15 UTC

Last modified

2026-06-17 06:07 UTC

Added to CISA KEV

2023-11-13

Exploit probability

90.0% · EPSS, next 30 days

Weakness

CWE-473

Record status

Analyzed

Affected

• Juniper Junos < 20.4
• Juniper Junos 20.4
• Juniper Junos 21.1
• Juniper Junos 21.2
• Juniper Junos 21.3
• Juniper Junos 21.4
• Juniper Junos 22.1
• Juniper Junos 22.2

Attack profile CVSS 3.1 · 5.3

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-36844.md and follow it. Check whether this project is affected by CVE-2023-36844. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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