#VU118602 Buffer underflow in FortiOS - CVE-2025-53843
Published: November 18, 2025
Vulnerability identifier: #VU118602
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2025-53843
CWE-ID: CWE-124
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
FortiOS
FortiOS
Software vendor:
Fortinet, Inc
Fortinet, Inc
Description
The vulnerability allows a remote authenticated user to execute arbitrary code.
The vulnerability exists due to buffer underwrite ('buffer underflow') in CAPWAP daemon. A remote authenticated attacker can execute arbitrary code or command as a low privileged user via specially crafted packets.Successful exploitation would require a large amount of effort in preparation because of stack protection and ASLR. Additionally, attacker must be able to pose as an authorized FortiAP or FortiExtender.
Remediation
Install update from vendor's website.