Second-Order OS Command Injection via JSON Input on start vnc feature
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
CVSSv3 Score: 9.1 An improper neutralization of special elements used in an OS command vulnerability [CWE-78] in FortiSandbox, FortiSandbox Cloud and FortiSandbox PaaS WEB UI may allow an unauthenticated attacker to execute unauthorized commands via specifically crafted HTTP requests. Revised on 2026-06-09 00:00:00
CSIRTS triage
- What
- An improper neutralization of special elements used in an OS command vulnerability allows unauthenticated attackers to execute unauthorized commands.
- Who is affected
- Users of FortiSandbox, FortiSandbox Cloud, and FortiSandbox PaaS WEB UI.
- Urgency
- Remediation is critical due to the high severity and potential for remote code execution.
- Action
- Apply the latest security updates from Fortinet.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://fortiguard.fortinet.com/psirt/FG-IR-26-141
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation confirmedCVE-2026-25089Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 99.4% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-25089 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- criticalexploitedFortinet security advisory (AV26-351) – Update 2cccs
- criticalexploitedFortinet security advisory (AV26-568) – Update 1cccs
- highexploitedCISA Adds Three Known Exploited Vulnerabilities to Catalogcisa
- criticalexploitedCVE-2026-25089: Fortinet FortiSandbox OS Command Injection Vulnerabilitycisa-kev
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