CVE-2023-36844
MEDIUMCISA KEVEPSS 100th pctlDescription
A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series 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. This issue affects Juniper Networks Junos OS on EX 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 22.3R3-S1; * 22.4 versions prior to 22.4R2-S2, 22.4R3; * 23.2 versions prior to 23.2R1-S1, 23.2R2.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
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.
Remediation due: 2023-11-17
References
Related Vulnerabilities
Other CWE-473 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-36845 | Critical | 9.8 | 94% | KEV | Fix |
| CVE-2026-28411 | Critical | 9.8 | 0.6% | - | Fix |
| CVE-2024-27489 | High | 7.5 | 0.4% | - | - |
| CVE-2026-40285 | High | 8.8 | 0.3% | - | - |
Common questions
How do I fix CVE-2023-36844?
Upgrade junos to 20.4 or later.
Is CVE-2023-36844 being actively exploited?
Yes. CVE-2023-36844 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2023-11-17. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2023-36844?
CVE-2023-36844 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2023-36844 affect?
Published advisories record a fix for junos (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2023-36844
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-24.