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CVE-2023-36844

5.3, medium Known exploited

Juniper Junos OS EX Series PHP External Variable Modification Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
5.3, medium medium CVSS v3.1
EPSS, next 30 days
90% higher than 99.7% of scored CVEs
Exploitation
Confirmed in the wild
Published
17 Aug 20233 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 13 Nov 2023. US federal agencies had to remediate by 17 Nov 2023, a deadline that has passed.

Required action. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Description

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.

Details

Vendor
Juniper
Product
Junos OS
Weakness
CWE-473 (opens in a new tab)
Status
Analyzed
Updated
17 Jun 2026
Assigner
sirt@juniper.net

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References 3

Exploit code 1

Advisories 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Juniper CVEs

Every Juniper CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability KEV EPSS 2% 4.4, medium
  • CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability KEV EPSS 1% 5.3, medium
  • CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification Vulnerability KEV EPSS 95% 9.8, critical
  • CVE-2023-36846 Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability KEV EPSS 93% 5.3, medium
  • CVE-2023-36847 Juniper Junos OS EX Series Missing Authentication for Critical Function Vulnerability KEV EPSS 83% 5.3, medium
  • CVE-2020-1631 Juniper Junos OS Path Traversal Vulnerability KEV EPSS 5% 9.8, critical
  • CVE-2015-7755 Juniper ScreenOS Improper Authentication Vulnerability KEV EPSS 61% 9.8, critical

Beyond this page

Is CVE-2023-36844 in your network?

This page tells you how dangerous CVE-2023-36844 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2023-36844 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2023-36844 comes with the devices to patch.

    Learn more about EXYS7600 OCELOT

  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.