{"id":"CVE-2023-36844","published":"2023-08-17T20:15:10Z","modified":"2026-06-17T06:07:12Z","title":"Juniper Junos OS EX Series PHP External Variable Modification Vulnerability","vendor":"Juniper","product":"Junos OS","tier":"core","eol":null,"description":{"text":"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.\n\nUsing a crafted request an attacker is able to modify \n\ncertain PHP environment variables leading to partial loss of integrity, which may allow chaining to other vulnerabilities.\nThis issue affects Juniper Networks Junos OS on EX Series:\n\n\n\n  *  All versions prior to 20.4R3-S9;\n  *  21.1 versions 21.1R1 and later;\n  *  21.2 versions prior to 21.2R3-S7;\n  *  21.3 versions \n\nprior to \n\n 21.3R3-S5;\n  *  21.4 versions \n\nprior to \n\n21.4R3-S5;\n  *  22.1 versions \n\nprior to \n\n22.1R3-S4;\n  *  22.2 versions \n\nprior to \n\n22.2R3-S2;\n  *  22.3 versions \n\nprior to 22.3R3-S1;\n  *  22.4 versions \n\nprior to \n\n22.4R2-S2, 22.4R3;\n  *  23.2 versions prior to \n\n23.2R1-S1, 23.2R2.","provenance":"source","from":"NVD"},"summary":{"text":"A PHP External Variable Modification flaw in the J-Web interface of Juniper Networks Junos OS on EX Series switches lets an attacker modify certain important PHP environment variables, causing a partial loss of integrity that may enable chaining to other vulnerabilities. The attacker needs only network access to the device and sends a crafted request, with no authentication or user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:11:36Z"},"cvss":{"score":5.3,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","provenance":"source","from":"NVD"},"epss":{"score":0.89958,"percentile":0.99792,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2023-11-13","dueDate":"2023-11-17","ransomware":false,"requiredAction":"Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","notes":"https://supportportal.juniper.net/s/article/2023-08-Out-of-Cycle-Security-Bulletin-Junos-OS-SRX-Series-and-EX-Series-Multiple-vulnerabilities-in-J-Web-can-be-combined-to-allow-a-preAuth-Remote-Code-Execution?language=en_US ;  https://nvd.nist.gov/vuln/detail/CVE-2023-36844","provenance":"source"},"vulncheckKev":{"dateAdded":"2023-08-29","exploitedFirstSeen":"2023-08-29","ransomware":true,"evidence":[{"url":"https://twitter.com/Shadowserver/status/1696512418036486246","date":"2023-08-29"},{"url":"https://supportportal.juniper.net/s/article/2023-08-Out-of-Cycle-Security-Bulletin-Junos-OS-SRX-Series-and-EX-Series-Multiple-vulnerabilities-in-J-Web-can-be-combined-to-allow-a-preAuth-Remote-Code-Execution","date":"2023-11-08"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2023-11-13"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-18&host_type=src&vulnerability=cve-2023-36844","date":"2023-11-18"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-23&host_type=src&vulnerability=cve-2023-36844","date":"2023-11-23"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-27&host_type=src&vulnerability=cve-2023-36844","date":"2023-11-27"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-28&host_type=src&vulnerability=cve-2023-36844","date":"2023-11-28"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-11-29&host_type=src&vulnerability=cve-2023-36844","date":"2023-11-29"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-12-01&host_type=src&vulnerability=cve-2023-36844","date":"2023-12-01"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2023-12-02&host_type=src&vulnerability=cve-2023-36844","date":"2023-12-02"}],"evidenceTotal":533,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-473","name":"PHP External Variable Modification"}],"references":[{"url":"http://packetstormsecurity.com/files/174865/Juniper-SRX-Firewall-EX-Switch-Remote-Code-Execution.html","tags":["Exploit","Third Party Advisory","VDB Entry"]},{"url":"https://supportportal.juniper.net/JSA72300","tags":["Vendor Advisory"]},{"url":"http://packetstormsecurity.com/files/174865/Juniper-SRX-Firewall-EX-Switch-Remote-Code-Execution.html","tags":["Exploit","Third Party Advisory","VDB Entry"]},{"url":"https://supportportal.juniper.net/JSA72300","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-36844","tags":["US Government Resource"]}],"techniques":[{"id":"T1203","name":"Exploitation for Client Execution","tactics":["execution"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Other","mappingType":"exploitation_technique","evidence":[],"comment":"This vulnerability is exploited through a PHP External Variable Modification flaw in the J-Web component of Juniper Networks Junos OS on EX Series devices. Attackers first use this vulnerability to gain control over certain environment variables by sending a crafted request, which allows them to manipulate these variables without authentication.","confidence":"low","confidenceNote":"server-side bug exploitable without user interaction; client-execution technique does not fit"},{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Other","mappingType":"primary_impact","evidence":[],"comment":"This vulnerability is exploited through a PHP External Variable Modification flaw in the J-Web component of Juniper Networks Junos OS on EX Series devices. Attackers first use this vulnerability to gain control over certain environment variables by sending a crafted request, which allows them to manipulate these variables without authentication.","confidence":"medium","confidenceNote":"CTID KEV capability group \"other\" is generic"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2023-40764","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-40764","exploited":true,"exploitedSince":"2023-11-13","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":3,"skipped":0,"earliest":"2023-08-25","earliestUrl":"https://github.com/watchtowrlabs/juniper-rce_cve-2023-36844","repos":[{"name":"watchtowrlabs/juniper-rce_cve-2023-36844","url":"https://github.com/watchtowrlabs/juniper-rce_cve-2023-36844","stars":114,"created":"2023-08-25"},{"name":"r3dcl1ff/CVE-2023-36844_Juniper_RCE","url":"https://github.com/r3dcl1ff/CVE-2023-36844_Juniper_RCE","stars":5,"created":"2023-09-24"},{"name":"Ap0dexMe0/CVE-2023-36844","url":"https://github.com/Ap0dexMe0/CVE-2023-36844","stars":0,"created":"2023-09-20"}]},"nuclei":[{"id":"CVE-2023-36844","name":"Juniper Devices - Remote Code Execution","severity":"medium","path":"http/cves/2023/CVE-2023-36844.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-36844.yaml"}],"first":{"date":"2023-08-25","source":"PoC-in-GitHub","url":"https://github.com/watchtowrlabs/juniper-rce_cve-2023-36844"},"provenance":"source"},"exploitRefs":["http://packetstormsecurity.com/files/174865/Juniper-SRX-Firewall-EX-Switch-Remote-Code-Execution.html"],"flow":[{"stage":"primary","techniques":["T1190"],"provenance":"source"},{"stage":"related","techniques":["T1203"],"provenance":"source","lowConfidence":true}],"timeline":[{"date":"2023-08-17","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-36844","provenance":"source"},{"date":"2023-08-25","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/watchtowrlabs/juniper-rce_cve-2023-36844","provenance":"source"},{"date":"2023-08-29","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://twitter.com/Shadowserver/status/1696512418036486246","provenance":"source"},{"date":"2023-11-13","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2023-11-13","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-40764","provenance":"source"}],"speed":{"daysToPublicExploit":8,"firstExploitFrom":"PoC-in-GitHub","daysToKev":88},"priority":{"score":76.7,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 1159 days ago"},{"name":"Known ransomware use","points":10.0,"detail":"CISA KEV and VulnCheck KEV: Known"},{"name":"EPSS percentile","points":19.96,"detail":"percentile 0.9979"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 3 PoC-in-GitHub repos; 1 nuclei template"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":3.71,"detail":"base score 5.3"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}