CVE-2025-54353Network attack vector

Target-session script execution via HA path reflection

Published Dec 9, 2025 · Updated Jan 14, 2026

Reflected XSS in Fortinet FortiSandbox 4.0, 4.2, 4.4.0 through 4.4.7, and 5.0.0 through 5.0.2 allows remote attackers to inject script. The GUI's hcproxy handling of HA cluster paths fails to validate user-controlled values before returning them in a web page, enabling arbitrary JavaScript execution in a target user's session. Exploitation requires an HA cluster and target-user interaction; standalone deployments are unaffected, and the resulting script acts within the target user's application context.

CVSS severity5.4
Medium
EPSS probability6.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Fortinet FortiSandbox 4.0, 4.2, 4.4.0 through 4.4.7, and 5.0.0 through 5.0.2 allows remote attackers to inject script. The GUI's hcproxy handling of HA cluster paths fails to validate user-controlled values before returning them in a web page, enabling arbitrary JavaScript execution in a target user's session. Exploitation requires an HA cluster and target-user interaction; standalone deployments are unaffected, and the resulting script acts within the target user's application context.

The record

CVE
CVE-2025-54353
Published
Dec 9, 2025
Updated
Jan 14, 2026
Vendor
Fortinet
Product
FortiSandbox
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0.0 <=4.0.6
  2. Affected versionversion=4.2.1 <=4.2.8
  3. Affected versionversion=4.4.0 <=4.4.7
  4. Affected versionversion=5.0.0 <=5.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fortinet · FortiSandboxversion=4.0.0 <=4.0.6; version=4.2.1 <=4.2.8; version=4.4.0 <=4.4.7; version=5.0.0 <=5.0.2

Published CVSS scores

6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.4Fortinet, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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