ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2024-21620

Juniper Junos OS Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Published Aug 24, 2025 · catalog updated Aug 24, 2025 · Juniper Junos OS

Patch now

CVE-2024-21620 is in the CISA known-exploited catalog. Confirm Juniper Junos OS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Unknown—
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.91%
Remediation
Remediation guidance
Affected products
vendor Juniper Junos OS

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Juniper Junos OSversion unspecified

How to fix CVE-2024-21620

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2024-21620 is in the CISA known-exploited catalog. Confirm Juniper Junos OS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 0.91%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 24, 2025 · VulnCheck KEV

    Detected

    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 webau

  2. Aug 24, 2025 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2024-21620

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2024-21620

    30-day exploitation probability 0.9%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-2024-21620

    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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.