High

OS Command Injection in Fortinet FortiSandbox Cloud vmimages Update Feature

IdentifiersCVE-2026-25836CWE-78· Improper Neutralization of Special…

CVE-2026-25836 is an OS command injection vulnerability in Fortinet FortiSandbox Cloud 5.0.4, identified in the vmimages update feature. According to the provided content, improper neutralization of special elements used in an OS command allows a privileged attacker with a super-admin profile and CLI access to execute unauthorized code or operating system commands via crafted HTTP requests. The issue is classified as CWE-78. The supporting content also states the flaw is reachable through the GUI/workflow associated with vmimages updates, indicating that attacker-controlled input is incorporated into backend command execution without sufficient sanitization or safe command construction.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows execution of arbitrary OS commands on the affected FortiSandbox Cloud instance. Because exploitation requires a super-admin level account and CLI access, the flaw is post-authentication and high-privilege, but the resulting impact can still be severe: unauthorized command execution, potential full system compromise, modification of appliance state, access to sensitive data processed by the platform, service disruption, and use of the appliance as a pivot point for further operations.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, restrict access to the FortiSandbox Cloud administrative interfaces, especially CLI/SSH and any management paths involved in vmimages updates, to a tightly controlled administrative network. Limit super-admin assignment to the minimum necessary personnel, enforce strong authentication and MFA where available, monitor for anomalous administrative actions and update-related requests, and consider temporarily disabling or operationally restricting the vmimages update workflow if feasible until a fixed version is deployed.

Remediation

Patch, then assume compromise.

Upgrade FortiSandbox Cloud to a vendor-fixed release that addresses CVE-2026-25836, and verify against Fortinet's FortiGuard PSIRT advisory and affected-version matrix. As part of remediation, review and reduce the number of accounts holding super-admin privileges, rotate credentials for privileged accounts that may have been exposed, and audit system and administrative logs for suspicious vmimages update activity, crafted HTTP requests, unexpected command execution, or other signs of post-authentication abuse.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

FortinetFortisandbox Cloudapplication

FortinetFortisandboxcloudapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

3 SOURCESView more in app

cyber security newsNews

Mar 10, 2026

Fortinet Security Update - Patch for Multiple Vulnerabilities That Enable Malicious Command Execution

OS command injection in FortiSandbox Cloud vmimages update feature allowing an authenticated attacker to execute arbitrary OS commands via the GUI.

What this page doesn’t show

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-25836

NVD

nvd.nist.gov/vuln/detail/CVE-2026-25836

MITRE CWE · CWE-78

Improper Neutralization of Special Elements…

Vendor Advisory

fortiguard.fortinet.com/psirt/FG-IR-26-096