Raw vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2025-53843 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Fortinet Fortios. Its CVSS base score is 7.5 (High).
Operationally, ranked at the 45th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-16 (Memory Protection) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-198006
Vulnerability Data
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
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Memory protection mechanisms (e.g., stack canaries, ASLR, DEP) directly block exploitation of the stack-based buffer overflow described in CVE-2025-53843.
Strict validation of all network packet inputs would have prevented the malformed packets from triggering the CWE-121 overflow in FortiOS.
Timely application of vendor patches eliminates the stack overflow vulnerability in the affected FortiOS versions before exploitation occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices directly prevent introduction of stack buffer overflows.
Vulnerability scanning can discover stack buffer overflows but does not prevent their introduction.
Patching eliminates known instances of the weakness after discovery.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing (fuzzing, static analysis) detects stack overflows before release.
Secure SDLC mandates buffer-safety practices that directly prevent stack overflows.
Application security requirements can specify buffer-size and input-validation rules.
Secure architecture principles include memory-safety and least-privilege stack usage.
Secure coding standards explicitly forbid unsafe buffer handling that causes CWE-121.
Change-management gates can enforce security reviews that catch buffer issues.