What is CVE-2025-53843?

CVE-2025-53843 is a high-severity vulnerability in Fortinet Fortios, classified under Stack-based Buffer Overflow. CVSS score: 7.5/10. Published 2025-11-18.

How severe is CVE-2025-53843?

High severity. CVSS v3 base score is 7.5 out of 10.

Buffer overflow in Fortinet Fortios

CVE-2025-53843

A stack-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 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions allows attacker to execute unauthorized code or commands via specially crafted packets

Vulnerability class: Buffer Overflow

EPSS: 0.006 (44.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Fortinet Fortios — versions 7.6.0, 7.4.0, 7.2.0

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

References

https://fortiguard.fortinet.com/psirt/FG-IR-25-358 (Vendor Advisory)
0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

Frequently asked questions

What is CVE-2025-53843?: CVE-2025-53843 is a high-severity vulnerability in Fortinet Fortios, classified under Stack-based Buffer Overflow. CVSS score: 7.5/10. Published 2025-11-18.
How severe is CVE-2025-53843?: High severity. CVSS v3 base score is 7.5 out of 10.