Stack-Based Buffer Overflow in Fortinet FortiAuthenticator
CVE-2026-126239

7.5HIGH

Key Information:

Vendor

Fortinet
Status
Fortiauthenticator
Vendor
CVE Published:
11 November 2026

What is CVE-2026-126239?

A stack-based buffer overflow vulnerability found in Fortinet FortiAuthenticator versions 8.0.0 to 8.0.3 and 6.6.0 to 6.6.10 may allow unauthenticated attackers to exploit the FSSO subsystem. By sending specially crafted HTTP requests, attackers can cause the system to crash, potentially disrupting service and compromising security. It is crucial for users to implement available mitigations to safeguard their systems against possible exploitation.

Affected Version(s)

FortiAuthenticator 8.0.0 <= 8.0.3

FortiAuthenticator 6.6.0 <= 6.6.10

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-254

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.