CVE-2024-21620
Published: April 11, 2026
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.
Technical Analysis
CVE-2024-21620 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2024-21620 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2024-21620 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1