Heap-based Buffer Overflow in Fortinet FortiOS and FortiSASE Products
CVE-2025-25249

7.4HIGH

Key Information:

Vendor: Fortinet
Status: Fortiswitchmanager; FortiOS
Vendor: CVE Published:; 13 January 2026

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👾 Exploit Exists🦅 CISA Reported📰 News Worthy

What is CVE-2025-25249?

A heap-based buffer overflow vulnerability in Fortinet's FortiOS and FortiSASE products allows attackers to execute unauthorized code or commands by sending specially crafted packets. This vulnerability affects a range of FortiOS versions, making it critical for users to apply the appropriate updates to mitigate potential exploitation.

CISA has reported CVE-2025-25249

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed CVE-2025-25249 as being exploited but is not known by the CISA to be used in ransomware campaigns. This is subject to change at pace

The CISA's recommendation is: 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.