SB2025111871 - Buffer underflow in FortiOS
Published: November 18, 2025
Security Bulletin ID
SB2025111871
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Buffer underflow (CVE-ID: CVE-2025-53843)
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.