CVE-2023-36845: Juniper Junos OS EX Series and SRX Series PHP External Variable Modification Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2023-11-13. EPSS: 95.1% chance of exploitation in the next 30 days.

A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series and SRX Series allows an unauthenticated, network-based attacker to remotely execute code. Using a crafted request which sets the variable PHPRC an attacker is able to modify the PHP execution environment allowing the injection und execution of code. This issue affects Juniper Networks Junos OS on EX Series and SRX 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 22.3R2-S2, 22.3R3-S1; * 22.4 versions prior to 22.4R2-S1, 22.4R3; * 23.2 versions prior to 23.2R1-S1, 23.2R2.

Affected products

• Juniper Junos: before 20.4 (fixed in 20.4); version 20.4 only; version 21.1 only; version 21.2 only; version 21.3 only; version 21.4 only; …

Published 2023-08-17. Last modified 2026-06-17.