# CVE-2026-59835 — Fortinet FortiSandbox

> As of 2026-07-16, CVE-2026-59835 is a HIGH-severity vulnerability in Fortinet FortiSandbox, CVSS v3.1 7.7, EPSS 0.3% (31.6th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-59835, most recently “FortiSandbox VNC Server Exposure Allows Unauthenticated Access to Scanning VMs (CVE-2026-59835)”.

**Last updated:** 2026-07-16

## What is CVE-2026-59835?

A exposure of resource to wrong sphere vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.2, FortiSandbox 4.4.3 through 4.4.8 may allow an unauthenticated attacker to access the VNC server of VMs performing scanning via network requests.

The record classifies CVE-2026-59835 under weakness class [CWE-668](https://intel.threadlinqs.com/cwe/CWE-668). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 106 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.7 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L/E:P/RL:O/RC:C`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 31.6% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-14, last modified 2026-07-16

## Is CVE-2026-59835 being exploited?

It currently carries a trending score of 21 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Fortinet](https://intel.threadlinqs.com/vendors/fortinet): FortiSandbox

## How to fix CVE-2026-59835

No vendor patch reference has been recorded for CVE-2026-59835 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-59835

1 tracked threat in the Threadlinqs corpus references CVE-2026-59835, either in the campaign’s CVE list or as an indicator on the campaign record.

- [FortiSandbox VNC Server Exposure Allows Unauthenticated Access to Scanning VMs (CVE-2026-59835)](https://intel.threadlinqs.com/threat/TL-2026-1319) — HIGH · 2026-07-14

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-10-10.

**Other references**

- [fortiguard.fortinet.com](https://fortiguard.fortinet.com/psirt/FG-IR-26-145)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-59835
Full detection coverage and IOCs for threats exploiting CVE-2026-59835 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp