# CVE-2026-26248: Fortinet FortiSandbox cross-site scripting in web UI

Source: https://junglewise.ai/threats/cve-2026-26248-a-improper-neutralization-of-input-during-web-page-generation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-10. Updated: 2026-11-10  
License: CC BY 4.0 with a link back

CVE-2026-26248 · Severity: high · CVSS 8.8 · Published 2026-11-10

FortiSandbox is a malware and threat detection appliance used to analyze suspicious files and URLs. An unauthenticated attacker can inject malicious scripts into the web interface through crafted HTTP requests, allowing them to steal session credentials, redirect users to malicious sites, or perform unauthorized actions on behalf of legitimate users.

Technologies: [Fortinet FortiSandbox](https://junglewise.ai/threats/technologies/fortisandbox), [Fortinet FortiSandbox PaaS](https://junglewise.ai/threats/technologies/fortisandbox-paas), [Fortinet Fortisandbox Cloud](https://junglewise.ai/threats/technologies/fortisandbox-cloud). Vendors: [Fortinet](https://junglewise.ai/threats/vendors/fortinet).

## Quick answers

**Is CVE-2026-26248 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-26248 being exploited in the wild.

**How severe is CVE-2026-26248?** High severity, with a CVSS score of 8.8, published 10 November 2026.

**Which products and versions are affected?** Fortinet FortiSandbox 5.0.0 through 5.0.5, 4.4.0 through 4.4.8; Fortinet FortiSandbox PaaS 5.0.4 through 5.0.5; Fortinet Fortisandbox Cloud 5.0.4 through 5.0.5.

**Is there a fix for CVE-2026-26248?** Yes: fixed in FortiSandbox 5.0.6 or above, 4.4.9 or above; FortiSandbox Cloud 5.0.6 or above; FortiSandbox PaaS 5.0.6 or above. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-26248 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-26248?** Check whether you run Fortinet FortiSandbox, Fortinet FortiSandbox PaaS or Fortinet Fortisandbox Cloud at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in FortiSandbox 5.0.6 or above, 4.4.9 or above; FortiSandbox Cloud 5.0.6 or above; FortiSandbox PaaS 5.0.6 or above

## Technical details

A CWE-79 cross-site scripting (XSS) vulnerability exists in the FortiSandbox web UI that fails to properly neutralize user input. An unauthenticated attacker can exploit this via crafted HTTP requests combined with social engineering to inject arbitrary JavaScript. The vulnerability affects multiple product lines and versions with a CVSS v3 score of 7.9.

## Affected products

- Fortinet FortiSandbox 5.0.0 through 5.0.5, 4.4.0 through 4.4.8
- Fortinet FortiSandbox Cloud 5.0.4 through 5.0.5
- Fortinet FortiSandbox PaaS 5.0.4 through 5.0.5

## Timeline

- 2026-11-10: disclosed

## References

- [https://fortiguard.fortinet.com/psirt/FG-IR-26-142](https://fortiguard.fortinet.com/psirt/FG-IR-26-142)

## Related threats

- [Fortinet FortiSandbox authentication bypass in web management interface](https://junglewise.ai/threats/cve-2026-107656-an-authentication-bypass-using-an-alternate-path-or-channel)
- [Fortinet FortiSandbox hard-coded cryptographic key in API](https://junglewise.ai/threats/cve-2026-106172-a-use-of-hard-coded-cryptographic-key-vulnerability-in-fortinet)
- [Fortinet FortiSandbox persistent denial of service in GUI and CLI](https://junglewise.ai/threats/cve-2026-106170-an-uncaught-exception-vulnerability-cwe-248-vulnerability-in)
- [Fortinet FortiSandbox command injection in HTTP requests](https://junglewise.ai/threats/cve-2026-84387-fortinet-fortisandbox-command-injection-in-http-requests)
- [Fortinet FortiSandbox improper access control in web UI](https://junglewise.ai/threats/cve-2026-26084-fortinet-fortisandbox-improper-access-control-in-web-ui)