FortiOS
CVE-2025-53844: Out-of-bounds write in FortiOS
A out-of-bounds write 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 allows attacker to execute unauthorized code or commands via specially crafted packets.
Published
ExploitedNot in CISA KEV
Ransomware useNot reportedPer CISA
SeverityHIGHCVSS 3.1 8.3
EPSS0.56%Chance of exploitation in 30 days
Public exploitNot tracked
FixAvailable
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| FortiOS 7.6.0 to 7.6.3 | 7.6.4 or later |
| FortiOS 7.4.0 to 7.4.8 | 7.4.9 or later |
| FortiOS 7.2.0 to 7.2.11 | 7.2.12 or later |
| FortiOS 7.0.0 to 7.0.17 | 7.0.18 or later |
| FortiOS 6.4.0 to 6.4.16 | Upgrade past 6.4.16; see the advisory |
| FortiOS 6.2.0 to 6.2.17 | Upgrade past 6.2.17; see the advisory |
| FortiOS 6.0.0 to 6.0.18 | Upgrade past 6.0.18; see the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A out-of-bounds write 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 allows attacker to execute unauthorized code or commands via specially crafted packets.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 10 Oct 2026.