CRITICAL CVE-2025-25249
CWE-122

Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability

Published by Tech Mentor Threat Intelligence Team
// Technical Threat Dossier
Vulnerability ID (CVE ID): CVE-2025-25249
Estimated Severity Level: CRITICAL
Affected Systems & Software:
  • Fortinet Multiple Products
Patch / Update Availability: 2026-09-09
Threat Classification & Indicators (Threat Intel):
CWE-122

Threat Scope & Field Impact:

Cybersecurity threat intelligence monitors have confirmed active in-the-wild exploitation of CVE-2025-25249 targeting Fortinet Multiple Products. Successful exploitation allows threat actors to compromise application integrity and threaten user data confidentiality.

Technical Advisory Summary: Fortinet FortiOS, FortiSwitchManager, and FortiSASE contain a heap-based buffer overflow vulnerability that allows an attacker to execute unauthorized code or commands via specially crafted packets.

CISA KEV Catalog: Officially cataloged by CISA as actively weaponized against production targets.

Recommended Mitigation & Action:

  • Required Vendor Action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
  • Remediation Timeline: Apply security patches immediately (Federal Remediation Due Date: 2026-09-12).
  • Defensive Telemetry: We advise journalists, frontline defenders, and civil society organizations utilizing this platform to inspect updates and isolate unpatched endpoints.
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