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.
- Vendor
- Juniper
- Product
- Junos OS
- CVSS
- 5.3
- EPSS (exploit probability)
- 90.0%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2023-36844 being exploited?
Yes. CISA added CVE-2023-36844 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 90.0% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-10-21. Full cross-catalog view: /kev-comparison
What to do
CISA required actionApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
US federal civilian agencies must remediate by (4 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Juniper Junos OS CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability | [ MEDIUM ] | 4.4 | 1.7% | |
| CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability | [ MEDIUM ] | 5.3 | 1.1% | |
| CVE-2023-36847 Juniper Junos OS EX Series Missing Authentication for Critical Function Vulnerability | [ MEDIUM ] | 5.3 | 83.5% | |
| CVE-2023-36846 Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability | [ MEDIUM ] | 5.3 | 93.5% | |
| CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification Vulnerability | [ CRITICAL ] | 9.8 | 95.1% | |
| CVE-2020-1631 Juniper Junos OS Path Traversal Vulnerability | [ HIGH ] | 8.8 | 4.9% |