Fortinet · Multiple Products
CVE-2025-25249
Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability
What it is
A heap-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11, FortiOS 7.0.0 through 7.0.17, FortiOS 6.4 all versions, FortiSwitchManager 7.2.0 through 7.2.6, FortiSwitchManager 7.0.0 through 7.0.5 allows attacker to execute unauthorized code or commands via specially crafted packets
CISA: 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.
What to do
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.
Deadline for US federal agencies: September 12, 2026
- Added to the CISA list
- September 9, 2026
- Published
- January 13, 2026
- Severity
- High 7.4 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 3.7% in the top 10.2% of all known vulnerabilities
- Weakness
- CWE-122 CWE-787
- More details
- NVD · CVE.org · CISA
All references (1)
More exploited flaws from Fortinet
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Oct 16, 2026 | Path Traversal | Multiple Products | Medium 5.4 | 1.3% |
| Jan 27, 2026 | Authentication Bypass Using an Alternate Path or Channel | Multiple Products | Critical 9.4 | 87% |
| Dec 16, 2025 | Improper Verification of Cryptographic Signature | Multiple Products | Critical 9.1 | 68% |
| May 14, 2025 | Stack-Based Buffer Overflow | Multiple Products | Critical 9.6 | 31% |
| Oct 9, 2024 | Format String | Multiple Products | Critical 9.8 | 62% |
| Oct 11, 2022 | Authentication Bypass | Multiple Products | Critical 9.8 | >99.9% |
| Oct 1, 2026 | Path Traversal | FortiMail | Critical 9.8 | 4.6% |
| Jul 27, 2026 | Exposure of Sensitive Information to an Unauthorized Actor | FortiOS | Medium 5.3 | 29% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.