Juniper · Junos OS
CVE-2023-36845
Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variable
What it is
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.
CISA: Juniper Junos OS on EX Series and SRX Series contains a PHP external variable modification vulnerability that allows an unauthenticated, network-based attacker to control an important environment variable. 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.
What to do
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: November 17, 2023
More exploited flaws from Juniper
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Mar 13, 2025 | Improper Isolation or Compartmentalization | Junos OS | Medium 6.7 | 1.7% |
| Nov 13, 2023 | EX Series PHP External Variable Modification | Junos OS | Medium 5.3 | 90% |
| Nov 13, 2023 | SRX Series Missing Authentication for Critical Function | Junos OS | Medium 5.3 | 93% |
| Nov 13, 2023 | EX Series Missing Authentication for Critical Function | Junos OS | Medium 5.3 | 83% |
| Nov 13, 2023 | SRX Series Missing Authentication for Critical Function | Junos OS | Medium 5.3 | 1.1% |
| Mar 25, 2022 | Path Traversal | Junos OS | High 8.8 | 4.9% |
| Oct 2, 2025 | Improper Authentication | ScreenOS | Critical 9.8 | 61% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.