---
title: "CVE-2023-36846: Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability"
url: https://erroneo.us/security/cve/CVE-2023-36846/
description: "CVE-2023-36846 (Juniper Junos OS): Exploited in the wild (CISA KEV). A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos…"
type: vulnerability-record
section: "Security Digest"
date_published: 2023-08-17
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2023-36846"
kev: true
cvss: 5.3
epss: 0.93473
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2023-36846: Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Juniper Junos OS. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2023-11-13, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2023-11-17 ; treat that as the outer limit, not the target.
- EPSS 93.5% , percentile 99.8: FIRST’s model estimates a 93.5% chance of exploitation activity in the next 30 days, higher than 99.8% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity. With a specific request to user.php that doesn't require authentication an attacker is able to upload arbitrary files via J-Web, leading to a loss of integrity for a certain part of the file system, which may allow chaining to other vulnerabilities. This issue affects Juniper Networks Junos OS on SRX Series: All versions prior to 20.4R3-S8; 21.1 versions 21.1R1 and later; 21.2 versions prior to 21.2R3-S6; 21.3 versions prior to 21.3R3-S5; 21.4 versions prior to 21.4R3-S5; 22.1 versions prior to 22.1R3-S3; 22.2 versions prior to 22.2R3-S2; 22.3 versions prior to 22.3R2-S2, 22.3R3; 22.4 versions prior to 22.4R2-S1, 22.4R3.

## Affected products (CVE record)

- Juniper Networks Junos OS: < 20.4R3-S8, 21.1 < 21.1*, 21.2 < 21.2R3-S6, 21.3 < 21.3R3-S5, 21.4 < 21.4R3-S5, 22.1 < 22.1R3-S3, 22.2 < 22.2R3-S2, 22.3 < 22.3R2-S2, 22.3R3, 22.4 < 22.4R2-S1, 22.4R3

## Severity

- juniper CVSS 3.1: 5.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`

## Exploitation

- CISA KEV: added 2023-11-13; federal due date 2023-11-17. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 93.47% probability of exploitation activity in the next 30 days; percentile 99.8.

## Sources

- [supportportal.juniper.net](https://supportportal.juniper.net/JSA72300)
- [Listed in CISA KEV notes (supportportal.juniper.net)](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)
- [CVE.org record CVE-2023-36846](https://www.cve.org/CVERecord?id=CVE-2023-36846)
- [NVD entry CVE-2023-36846](https://nvd.nist.gov/vuln/detail/CVE-2023-36846)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-36846)

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Source page: https://erroneo.us/security/cve/CVE-2023-36846/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt