CVE-2023-36844 | Junos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variables

Exp

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.

Published: 2023-08-17 Last update: 2025-10-24 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-36844 is rated Critical Active Threat (81.1/100): CVSS Medium severity, with high exploitation likelihood (EPSS 94.22%, 100th percentile). CISA KEV confirms active exploitation (added 2023-11-13) affecting Juniper / Junos OS. a weakness (CWE-473) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2023-36844

Name: Juniper Junos OS EX Series PHP External Variable Modification Vulnerability · CISA KEV detail

Exploit added: 2023-11-13

Action due: 2023-11-17

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

Public exploit references (Exploit-DB) for CVE-2023-36844

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-36844

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-01 94.30% 94.22% -0.08%
2 2025-11-21 93.95% 94.30% +0.35%
3 2025-11-18 — 93.95% —

Full EPSS history (45 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-36844

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]

Weakness enumeration for CVE-2023-36844

Affected software / configurations for CVE-2023-36844

Vendor Product Version Raw CPE
juniper junos < 20.4 cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:-:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r1-s1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r2:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r2-s1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r2-s2:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s1:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s2:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s3:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s4:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s5:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s6:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s7:*:*:*:*:*:*
juniper junos 20.4 cpe:2.3:o:juniper:junos:20.4:r3-s8:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r1:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r1-s1:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r2:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r2-s1:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r2-s2:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r3:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r3-s1:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r3-s2:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r3-s3:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r3-s4:*:*:*:*:*:*
juniper junos 21.1 cpe:2.3:o:juniper:junos:21.1:r3-s5:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:-:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r1-s1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r1-s2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r2-s1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r2-s2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s1:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s2:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s3:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s4:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s5:*:*:*:*:*:*
juniper junos 21.2 cpe:2.3:o:juniper:junos:21.2:r3-s6:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:-:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r1-s1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r1-s2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r2-s1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r2-s2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s1:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s2:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s3:*:*:*:*:*:*
juniper junos 21.3 cpe:2.3:o:juniper:junos:21.3:r3-s4:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:-:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r1-s1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r1-s2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r2-s1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r2-s2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s1:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s2:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s3:*:*:*:*:*:*
juniper junos 21.4 cpe:2.3:o:juniper:junos:21.4:r3-s4:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r1-s1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r1-s2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r2-s1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r2-s2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3-s1:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3-s2:*:*:*:*:*:*
juniper junos 22.1 cpe:2.3:o:juniper:junos:22.1:r3-s3:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r1:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r1-s1:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r1-s2:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r2:*:*:*:*:*:*
juniper junos 22.2 cpe:2.3:o:juniper:junos:22.2:r2-s1:*:*:*:*:*:*

References for CVE-2023-36844

cvelogic Threat Intelligence