Junos OS (SRX firewalls)
CVE-2023-36845: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variable
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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS (EX Series, SRX Series) 0 | 20.4R3-S9 or later |
| Junos OS (EX Series, SRX Series) 21.1 | 21.1* or later |
| Junos OS (EX Series, SRX Series) 21.2 | 21.2R3-S7 or later |
| Junos OS (EX Series, SRX Series) 21.3 | 21.3R3-S5 or later |
| Junos OS (EX Series, SRX Series) 21.4 | 21.4R3-S5 or later |
| Junos OS (EX Series, SRX Series) 22.1 | 22.1R3-S4 or later |
| Junos OS (EX Series, SRX Series) 22.2 | 22.2R3-S2 or later |
| Junos OS (EX Series, SRX Series) 22.3 | 22.3R2-S2, 22.3R3-S1 or later |
| Junos OS (EX Series, SRX Series) 22.4 | 22.4R2-S1, 22.4R3 or later |
| Junos OS (EX Series, SRX Series) 23,2 | 23.2R1-S1, 23.2R2 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
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.
Am I affected?
The following minimal configuration is necessary:
[system services web-management http]or
[system services web-management https]
Workarounds
Disable J-Web, or limit access to only trusted hosts.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
CISA lists this CVE as exploited in the wild since 13 Nov 2023.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.