CVE-2025-25249

Fortinet Multiple Products: Heap-based Buffer Overflow

As of , CVE-2025-25249 in Fortinet Multiple Products is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch now.

Exploited
Yes: CISA listed it on 9 September 2026
US federal deadline
12 September 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
Forensic triage
Required by CISA under BOD 26-04Agencies must also look for signs that attackers already got in.
EPSS score
0.04Higher than 89% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: fortiguard.fortinet.comLinks below, from CISA's entry.

What CISA says 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.

CISA's required action

What the flaw 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.

CISA's description

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

The CVE record's description, from fortinet

CVE published
13 January 2026
Assigned by
fortinet
CVSS
7.4 High (CVSS 3.1, from the CNA)
CWE-122
Heap-based Buffer Overflow
CWE-787
Out-of-bounds Write
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Multiple Products: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2022-40684Authentication BypassFortinet Multiple ProductsPatch this weekRansomware use; Metasploit module; EPSS 0.990.99
CVE-2026-24858Authentication Bypass Using an Alternate Path or ChannelFortinet Multiple ProductsPatch this weekEPSS 0.860.86
CVE-2025-59718Improper Verification of Cryptographic SignatureFortinet Multiple ProductsPatch this weekEPSS 0.680.68
CVE-2024-23113Format StringFortinet Multiple ProductsPatch this weekEPSS 0.620.62
CVE-2025-32756Stack-Based Buffer OverflowFortinet Multiple ProductsPatch soon0.30

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