Exploited vulnerability · CISA KEV

Is CVE-2025-25249 exploited? Yes: in CISA KEV since 9 Sep 2026

Gociux · Fortinet Multiple Products · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2025-25249, Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 9 Sep 2026, 239 days after it was published. It affects Fortinet Multiple Products, an internet-facing product of the kind attackers use for initial access. If you run it, CISA's required action 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.

What it is

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

1. Check whether you run it. Look for Multiple Products in your asset inventory, including appliances and cloud images. Stack check lists every exploited Fortinet CVE at once.
2. Apply the fix. 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.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 13 Jan 2026.
4. Get told next time. Email alerts when CISA adds a CVE for Fortinet.

Other exploited CVEs in Multiple Products

• CVE-2025-61624: Fortinet Multiple Products Path Traversal Vulnerability (16 Oct 2026)
• CVE-2026-24858: Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability (27 Jan 2026)
• CVE-2025-59718: Fortinet Multiple Products Improper Verification of Cryptographic Signature Vulnerability (16 Dec 2025)
• CVE-2025-32756: Fortinet Multiple Products Stack-Based Buffer Overflow Vulnerability (14 May 2025)
• CVE-2024-23113: Fortinet Multiple Products Format String Vulnerability (9 Oct 2024)
• CVE-2022-40684: Fortinet Multiple Products Authentication Bypass Vulnerability (11 Oct 2022)

References

• fortiguard.fortinet.com/psirt/FG-IR-25-084
• nvd.nist.gov/vuln/detail/CVE-2025-25249

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in September 2026 · Fortinet scorecard · act-now radar.