CVE-2023-36844
Published: November 13, 2023
Official Description
Juniper Junos OS on EX Series contains a PHP external variable modification vulnerability that 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.
CISA KEV Advisory
Juniper Junos OS EX Series PHP External Variable Modification Vulnerability
Juniper Junos OS on EX Series contains a PHP external variable modification vulnerability that 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.
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Risk Analysis
Juniper Junos OS on EX Series devices has a PHP external variable modification vulnerability that allows an unauthenticated, network-based attacker to control important environment variables. This can lead to partial loss of integrity and potentially be chained with other vulnerabilities, and its high EPSS score of 0.94302 indicates a very high likelihood of exploitation.
This vulnerability is actively exploited in the wild and is listed in CISA's KEV catalog, confirming its active use by attackers. It is remotely exploitable without authentication.
Administrators should immediately apply all available security updates for Juniper Junos OS on EX Series. Implement robust input validation and sanitization for all web-facing components.
Technical Analysis
CVE-2023-36844 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2023-36844 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (2)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2023-36844 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1