# CVE-2021-31384: Missing authorization in Junos OS

> Attackers can bypass interface restrictions to access J-Web management on Juniper SRX devices under specific configurations.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Oct 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-g6h6-r377-vh4m

## What is CVE-2021-31384?

CVE-2021-31384 is a high-severity missing authorization vulnerability in Juniper Junos, published on 19 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Due to a Missing Authorization weakness and Insufficient Granularity of Access Control in a specific device configuration, a vulnerability exists in Juniper Networks Junos OS on SRX Series whereby an attacker who attempts to access J-Web administrative interfaces can successfully do so from any device interface regardless of the web-management configuration and filter rules which may otherwise protect access to J-Web. This issue affects: Juniper Networks Junos OS SRX Series 20.4 version 20.4R1 and later versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.

Weakness: CWE-939 (Improper Authorization in Handler for Custom URL Scheme), CWE-862 (Missing Authorization), CWE-551 (Incorrect Behavior Order: Authorization Before Parsing and Canonicalization), CWE-285 (Improper Authorization), CWE-1220 (Insufficient Granularity of Access Control)

## Which versions are affected by CVE-2021-31384?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2021-31384?

No fix has been published for CVE-2021-31384 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31384 being exploited?

There is no known exploitation of CVE-2021-31384 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos

- [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild)
- [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild)
- [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild)
- [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)
- [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31384 and fix it if it is affected.

What it is: CVE-2021-31384 is a high-severity missing authorization vulnerability in Juniper Junos, published on 19 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-31384 in the wild and no public exploit code.

Affected product: Juniper Junos. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-31384/ (Markdown: https://insights.sbomify.com/CVE-2021-31384/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31384
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31384
- OSV: https://osv.dev/vulnerability/CVE-2021-31384

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31384/
Summaries are generated and may contain mistakes; the official description above is the record.