How severe is CVE-2023-36844?

CVE-2023-36844 has a CVSS 3.1 base score of 5.3 (MEDIUM). EPSS estimates a 90.0% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2023-36844: Junos OS: EX Series: A PHP vulnerability in J-Web

CISA Known Exploited Vulnerabilities

Juniper Junos OS EX Series PHP External Variable Modification Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2023-11-13

Remediation due

2023-11-17

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

CISA 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-2023-36844

Description

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.

Severity

CVSS 3.1 · CNA5.3 MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impacttotal

Affected Products

Vendor	Product	Affected versions
Juniper Networks	Junos OS	0 to <20.4R3-S9 21.1 to <21.1* 21.2 to <21.2R3-S6 21.3 to <21.3R3-S5 21.4 to <21.4R3-S5 22.1 to <22.1R3-S4 22.2 to <22.2R3-S2 22.3 to <22.3R3-S1 22.4 to <22.4R2-S2, 22.4R3 23.2 to <23.2R1-S1, 23.2R2

References

2 Links

Vendor advisories

https://supportportal.juniper.net/JSA72300

Other references

http://packetstormsecurity.com/files/174865/Juniper-SRX-Firewall-EX-Switch-Remote-Code-Execution.html

Record Details

Published

2023-08-17

Last updated

2025-10-21

Assigner (CNA)

juniper

Credited to

LYS, working with DEVCORE Internship Program

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Related Tool Categories

Tool categories that test for or protect against this vulnerability class.

CWE-473 · PHP External Variable Modification

Application Security Tools

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.