Full Report
Multiple vulnerabilities have been discovered in Fortinet products, the most severe of which could allow for arbitrary code execution.FortiAuthenticator is a centralized identity and access management (IAM) solution that secures network access by managing user identities, Multi-Factor Authentication (MFA), and certificate management.FortiClientEMS is a centralized management platform for deploying, configuring, monitoring, and enforcing security policies across numerous endpoints (computers) running the FortiClient agent.FortiClient is a Fabric Agent that delivers protection, compliance, and secure access in a single, modular lightweight client.FortiOS is the Fortinet’s proprietary Operation System which is utilized across multiple product lines.FortiSandbox is an advanced threat detection solution from Fortinet that uses sandboxing to analyze suspicious files and network traffic for advanced threats like zero-day malware and ransomware.Successful exploitation of the most severe of these vulnerabilities could allow for arbitrary code execution in the context of the affected service account. Depending on the privileges associated with the service account an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Service accounts that are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.
Analysis Summary
As a vulnerability research specialist, I have synthesized the key details from the provided advisory into an actionable summary focused on the known flaws. Note that specific CVSS scores and remediation details are not explicitly listed in the text for all CVEs, so placeholders reflect this gap.
# Vulnerability: Multiple Critical Vulnerabilities in Fortinet Products Leading to Potential Arbitrary Code Execution
## CVE Details
- **CVE ID:** Multiple (Key IDs mentioned: CVE-2026-21643, CVE-2025-52436, CVE-2026-22153, CVE-2025-62676, CVE-2025-62439, CVE-2025-64157, CVE-2026-21743)
- **CVSS Score:** Not explicitly provided for all CVEs; the most severe vulnerability **"could allow for arbitrary code execution."** (Implied High/Critical severity impact)
- **CWE:** CWE-89 (SQL Injection), CWE-79 (Cross-site Scripting), CWE-305 (Authentication Bypass by Primary Weakness), CWE-59 (Improper Link Resolution Before File Access), CWE-940 (Improper Verification of Source of a Communication Channel), CWE-134 (Use of Externally-Controlled Format String), CWE-862 (Missing Authorization), CWE-444 (HTTP Request Smuggling)
## Affected Systems
- **Products:** FortiAuthenticator, FortiClientEMS, FortiClientWindows, FortiOS, FortiSandbox, FortiGate (mentioned in a lower-severity flaw).
- **Versions:**
* **FortiAuthenticator:** 6.3 all versions, 6.4 all versions, 6.5 all versions, 6.6.0 through 6.6.6
* **FortiClientEMS:** 7.4.4
* **FortiClientWindows:** 7.0 all versions, 7.2.0 through 7.2.12, 7.4.0 through 7.4.4
* **FortiOS:** 6.4 all versions, 7.0 all versions, 7.2 all versions, 7.4.0 through 7.4.9, 7.6.0 through 7.6.4
* **FortiSandbox:** 4.0 all versions, 4.2 all versions, 4.4.0 through 4.4.7, 5.0.0 through 5.0.1
- **Configurations:** Specific LDAP server configurations required for CVE-2026-22153 (agentless VPN/FSSO bypass). Certain flaws require low-privilege local user (CVE-2025-62676) or authenticated admin access (CVE-2025-64157).
## Vulnerability Description
Multiple vulnerabilities exist across several Fortinet products. The most severe flaws allow unauthenticated remote attackers to achieve code execution, primarily via **SQL Injection (CWE-89)** in FortiClientEMS or **Cross-Site Scripting (CWE-79)** in FortiSandbox, both through crafted HTTP requests. Other critical flaws include an **Authentication Bypass (CWE-305)** in FortiOS fnbamd via LDAP configuration manipulation. Exploitation could result in arbitrary code execution in the context of the affected service account, potentially leading to data manipulation, program installation, or account creation, depending on the service account's privileges.
## Exploitation
- **Status:** No reports of exploitation in the wild currently exist as of the advisory date.
- **Complexity:** At least three critical paths allow for **unauthenticated** attacks (SQLi in EMS, XSS in Sandbox, Auth Bypass in FortiOS), suggesting **Low to Medium** complexity for initial access.
- **Attack Vector:** Network (Remote Unauthenticated) for the most severe flaws (EMS SQLi, Sandbox XSS, FortiOS Auth Bypass). Local for lower severity flaws (e.g., FortiClient Windows File Write).
## Impact
- **Confidentiality:** High (If exploited via high-privilege service accounts, unauthorized data viewing is possible).
- **Integrity:** High (Ability to install programs, change data, or create new accounts).
- **Availability:** Potentially High (Code execution leading to service disruption).
## Remediation
### Patches
*Specific patch versions are **not listed** in the context provided. Users must consult the referenced Fortinet PSIRT advisories for specific fixed versions.*
### Workarounds
No specific workarounds are detailed in the provided summary document. Immediate patching is implied as the primary mitigation, especially given the existence of unauthenticated remote execution paths.
## Detection
- **Indicators of Compromise:** Exploitation attempts matching the description of SQL Injection on web interfaces or crafted HTTP requests targeting the vulnerable components.
- **Detection Methods and Tools:** Monitor network traffic for suspicious, malformed, or overly long HTTP requests targeting FortiClientEMS or FortiSandbox management interfaces. For FSSO/VPN bypass, monitor LDAP connection logs for unexpected authentications.
## References
- FG-IR-25-661
- FG-IR-25-384
- FG-IR-25-795
- FG-IR-25-1052
- FG-IR-25-528
- FG-IR-25-667
- FG-IR-25-934
- FG-IR-25-093
- FG-IR-25-1142