---
title: "CISA Warns of Actively Exploited Fortinet FortiClient EMS Flaw"
short_title: "Critical Fortinet FortiClient EMS vulnerability added to CISA KEV"
description: "CISA adds CVE-2026-35616, a critical Fortinet FortiClient EMS flaw, to its KEV Catalog due to active exploitation. Federal agencies and organizations urged to patch immediately."
author: "Vitus"
date: 2025-01-24
categories: [Cybersecurity, Vulnerabilities]
tags: [cisa, fortinet, cve-2026-35616, vulnerability-management, threat-intelligence]
score: 0.85
cve_ids: [CVE-2026-35616]
---
TL;DR
CISA has added CVE-2026-35616, a critical improper access control vulnerability in Fortinet FortiClient EMS, to its Known Exploited Vulnerabilities (KEV) Catalog after confirming active exploitation. Federal agencies must remediate the flaw by the specified deadline, while all organizations are urged to prioritize patching to mitigate risks.
---
Main Content
The Cybersecurity and Infrastructure Security Agency (CISA) has escalated its response to an actively exploited vulnerability in Fortinet FortiClient EMS by adding it to the Known Exploited Vulnerabilities (KEV) Catalog. The flaw, tracked as CVE-2026-35616, poses a significant risk to federal agencies and enterprises due to its potential for unauthorized access and exploitation by malicious cyber actors.
Key Points
- CVE-2026-35616 is an improper access control vulnerability in Fortinet FortiClient EMS, enabling attackers to bypass security restrictions.
- CISA’s addition of the flaw to the KEV Catalog is based on evidence of active exploitation in the wild.
- Binding Operational Directive (BOD) 22-01 mandates Federal Civilian Executive Branch (FCEB) agencies to remediate the vulnerability by the specified due date.
- While BOD 22-01 applies only to federal agencies, CISA strongly recommends all organizations prioritize patching to reduce exposure to cyberattacks.
---
Technical Details
CVE-2026-35616 affects Fortinet FortiClient EMS, a centralized endpoint management solution used by enterprises to deploy, monitor, and secure endpoints. The vulnerability stems from improper access control mechanisms, allowing unauthorized users to execute actions with elevated privileges. Exploitation of this flaw could lead to unauthorized data access, lateral movement within networks, or deployment of malicious payloads.
Fortinet has released patches to address the vulnerability, and organizations are advised to apply them immediately. Additional details about the flaw, including indicators of compromise (IOCs), are available in Fortinet’s official security advisory.
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Impact Assessment
The inclusion of CVE-2026-35616 in CISA’s KEV Catalog underscores its severity and the urgency of remediation. Federal agencies face mandatory patching deadlines under BOD 22-01, while private sector organizations risk targeted attacks, data breaches, and operational disruptions if left unpatched.
Given Fortinet’s widespread use in enterprise environments, this vulnerability could serve as an entry point for ransomware, espionage, or other malicious activities. Organizations are encouraged to:
- Prioritize patching for all affected FortiClient EMS instances.
- Monitor networks for suspicious activity linked to exploitation attempts.
- Review access controls to ensure least-privilege principles are enforced.
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Mitigation Steps
1. Apply Fortinet’s patches immediately for all affected FortiClient EMS versions.
2. Isolate vulnerable systems from critical networks until patches are deployed.
3. Conduct a thorough audit of access logs to detect potential exploitation attempts.
4. Educate IT teams on recognizing signs of unauthorized access or lateral movement.
5. Subscribe to CISA alerts for updates on emerging threats and vulnerabilities.
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Conclusion
CISA’s addition of CVE-2026-35616 to the KEV Catalog serves as a critical reminder of the risks posed by unpatched vulnerabilities. Organizations must act swiftly to remediate the flaw, strengthen access controls, and enhance monitoring to defend against active threats. Failure to address this vulnerability could expose networks to severe cyberattacks with far-reaching consequences.
For more information, refer to CISA’s [official advisory](https://www.cisa.gov/news-events/alerts/2026/04/06/cisa-adds-one-known-exploited-vulnerability-catalog) and Fortinet’s security updates.
---
References
[^1]: CISA. "[CISA Adds One Known Exploited Vulnerability to Catalog](https://www.cisa.gov/news-events/alerts/2026/04/06/cisa-adds-one-known-exploited-vulnerability-catalog)". Retrieved 2025-01-24.
[^2]: Fortinet. "[Security Advisory for CVE-2026-35616](https://www.cve.org/CVERecord?id=CVE-2026-35616)". Retrieved 2025-01-24.
[^3]: CISA. "[Binding Operational Directive 22-01](https://www.cisa.gov/binding-operational-directive-22-01)". Retrieved 2025-01-24.