# CVE-2024-21620: Junos OS: SRX Series and EX Series: J-Web doesn't sufficiently sanitize input to prevent XSS

> An attacker can execute commands with target permissions via a crafted URL in J-Web, affecting Juniper SRX and EX Series devices.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 25 Jan 2024
- **Updated:** 29 May 2025
- **Also known as:** GHSA-mph2-x4gq-qj7g

## What is CVE-2024-21620?

CVE-2024-21620 is a high-severity cross-site scripting vulnerability in Juniper Junos, published on 25 Jan 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

An Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in J-Web of Juniper Networks Junos OS on SRX Series and EX Series allows an attacker to construct a URL that when visited by another user enables the attacker to execute commands with the target's permissions, including an administrator.

A specific invocation of the emit_debug_note method in webauth_operation.php will echo back the data it receives.

This issue affects Juniper Networks Junos OS on SRX Series and EX Series:
  *  All versions earlier than 20.4R3-S10;
  *  21.2 versions earlier than 21.2R3-S8;
  *  21.4 versions earlier than 21.4R3-S6;
  *  22.1 versions earlier than 22.1R3-S5;
  *  22.2 versions earlier than 22.2R3-S3;
  *  22.3 versions earlier than 22.3R3-S2;
  *  22.4 versions earlier than 22.4R3-S1;
  *  23.2 versions earlier than 23.2R2;
  *  23.4 versions earlier than 23.4R2.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2024-21620?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2024-21620?

No fix has been published for CVE-2024-21620 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21620 being exploited?

There is no known exploitation of CVE-2024-21620 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-2024-21620 and fix it if it is affected.

What it is: CVE-2024-21620 is a high-severity cross-site scripting vulnerability in Juniper Junos, published on 25 Jan 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2024-21620 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-2024-21620/ (Markdown: https://insights.sbomify.com/CVE-2024-21620/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21620
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21620
- OSV: https://osv.dev/vulnerability/CVE-2024-21620

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21620/
Summaries are generated and may contain mistakes; the official description above is the record.