Medium

Reflected XSS in FortiSandbox Operation Center

IdentifiersCVE-2025-61886CWE-79· Improper Neutralization of Input…

CVE-2025-61886 is a reflected cross-site scripting vulnerability in Fortinet FortiSandbox and FortiSandbox PaaS. The provided content states that it affects FortiSandbox 5.0.0 through 5.0.4 and FortiSandbox PaaS 5.0.0 through 5.0.4, and further identifies the vulnerable area as the Operation Center interface. The flaw is caused by improper neutralization of input during web page generation, allowing attacker-controlled input delivered via crafted HTTP requests to be reflected in the web interface and executed as script in a victim’s browser. The content also notes that the interface is accessible to unauthenticated users from an internal position.

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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 an attacker to execute arbitrary client-side script in the browser context of a user interacting with the vulnerable FortiSandbox Operation Center interface. Depending on the victim’s session and privileges, this can enable session theft, credential harvesting, unauthorized actions in the web interface, manipulation of displayed content, and pivoting to further compromise of the administrative workflow. Because the affected interface is noted as accessible without authentication from an internal position, internal attackers may be able to target users of the interface without first obtaining valid credentials.

Mitigation

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

Until patching is completed, restrict access to the FortiSandbox Operation Center interface to only trusted administrative networks and users, especially since the content indicates exposure to unauthenticated users from an internal position. Reduce attack surface by limiting internal reachability with network segmentation, reverse proxy or ACL controls, and by avoiding use of the interface from untrusted browsing contexts. Administrators should also monitor for suspicious crafted requests targeting the Operation Center and treat unexpected redirects or script execution in the GUI as potential exploitation attempts.

Remediation

Patch, then assume compromise.

Upgrade FortiSandbox and FortiSandbox PaaS to a fixed release that addresses CVE-2025-61886. The vulnerable versions identified in the provided content are 5.0.0 through 5.0.4 for both FortiSandbox and FortiSandbox PaaS, so remediation requires moving to a vendor-fixed version outside that affected range. Review Fortinet PSIRT guidance and product-specific release notes to select the appropriate patched build for the deployed branch.

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

FortinetFortisandboxapplication

FortinetFortisandbox Cloudapplication

FortinetFortisandboxpaasapplication

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

ACTIVITY FEED

Recent activity

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

2 SOURCESView more in app

help net securityNews

Apr 16, 2026

Fortinet fixes critical FortiSandbox vulnerabilities (CVE-2026-39813, CVE-2026-39808) - Help Net Security

A medium-severity vulnerability affecting FortiSandbox, FortiSandbox Cloud, or FortiSandbox PaaS that allows cross-site scripting attacks.

cyber security newsNews

Apr 14, 2026

Fortinet Patches 11 Vulnerabilities Across FortiSandbox, FortiOS, FortiAnalyzer, and FortiManager

A reflected XSS vulnerability in the FortiSandbox Operation Center interface that is accessible to unauthenticated users from an internal position.

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 activity