What is CVE-2025-25249?
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 record classifies CVE-2025-25249 under weakness class CWE-122. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 292 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.4 — HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:W/RC:C - EPSS (FIRST)
- 1.6% probability of exploitation in the next 30 days, higher than 75.7% of all scored CVEs
- CISA KEV
- Listed since 2026-09-09, federal remediation deadline 2026-09-12
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2026-01-13, last modified 2026-09-10
Is CVE-2025-25249 being exploited?
CISA added CVE-2025-25249 to the Known Exploited Vulnerabilities catalog on 2026-09-09, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-09-12 under BOD 22-01. It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.
Affected products and versions
- Fortinet: FortiSwitchManager, FortiOS
How to fix CVE-2025-25249
Because CVE-2025-25249 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-09-12. No vendor patch reference has been recorded for CVE-2025-25249 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2025-25249
2 tracked threats in the Threadlinqs corpus reference CVE-2025-25249, either in the campaign’s CVE list or as an indicator on the campaign record.
- Multiple Vulnerabilities in Fortigate NGFW on RUGGEDCOM APE1808 Devices (SSA-864900) — Including Actively Exploited FortiCloud SSO Bypass (CVE-2025-59718/-59719) and FortiOS Heap Overflow (CVE-2025-25249) — CRITICAL · 2026-09-13
- CVE-2025-25249: Fortinet Heap-Based Buffer Overflow Exploited to Deploy PivotC2 RAT on FortiGate Devices — CRITICAL · 2026-09-10
Sources
Enriched from CVE.org, FIRST EPSS, CISA KEV, GitHub Security Advisories. Last verified by Threadlinqs on .