Threat Intelligence / CVE / CVE-2026-26083

CVE-2026-26083 — Fortinet FortiSandbox Cloud

CVSS v3.1 9.1 (CRITICAL) · EPSS 0.0% (higher than 20.1% of all scored CVEs) · Priority 5.4/10 · Published 2026-05-12

As of 2026-05-13, CVE-2026-26083 is a CRITICAL-severity vulnerability in Fortinet FortiSandbox Cloud, CVSS v3.1 9.1, EPSS 0.0% (20.1th percentile). Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-26083, most recently “FortiSandbox VNC Server Exposure Allows Unauthenticated Access to Scanning VMs (CVE-2026-59835)”.

Last updated: 2026-05-13

What is CVE-2026-26083?

A missing authorization vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.1, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox Cloud 5.0.2 through 5.0.5, FortiSandbox PaaS 23.4 all versions, FortiSandbox PaaS 23.3 all versions, FortiSandbox PaaS 23.1 all versions, FortiSandbox PaaS 22.2 all versions, FortiSandbox PaaS 22.1 all versions, FortiSandbox PaaS 21.4 all versions, FortiSandbox PaaS 21.3 all versions, FortiSandbox PaaS 5.0.0 through 5.0.1, FortiSandbox PaaS 4.4.5 through 4.4.8 may allow an unauthenticated attacker to execute unauthorized code or commands via HTTP requests.

The record classifies CVE-2026-26083 under weakness class CWE-862. 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, integrity, availability. 3 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 123 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 9.1 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
EPSS (FIRST): 0.0% probability of exploitation in the next 30 days, higher than 20.1% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 5.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-05-12, last modified 2026-05-13

Is CVE-2026-26083 being exploited?

It currently carries a trending score of 10 in the Threadlinqs vulnerability feed.

Affected products and versions

Fortinet: FortiSandbox Cloud, FortiSandbox, FortiSandbox PaaS

How to fix CVE-2026-26083

No vendor patch reference has been recorded for CVE-2026-26083 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-2026-26083

2 tracked threats in the Threadlinqs corpus reference CVE-2026-26083, 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) — HIGH · 2026-07-14
Fortinet Critical Unauthenticated RCE — FortiAuthenticator CVE-2026-44277 & FortiSandbox CVE-2026-26083 — CRITICAL · 2026-05-12

Sources

Seeded from cveorg and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

fortiguard.fortinet.com

Full detection coverage & IOCs for threats exploiting CVE-2026-26083 are available via the Threadlinqs MCP server (Purple tier). View plans →

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