Read the docs
TI-2021-06335 Aliases CVE-2021-24018GHSA-q8x9-vj32-mh5w

Out-of-bounds write in Fortinet FortiOS

Priority MEDIUM 40CWE-787Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

A buffer underwrite vulnerability in the firmware verification routine of FortiOS before 7.0.1 may allow an attacker located in the adjacent network to potentially execute arbitrary code via a specifically crafted firmware image.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01035 64th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FortinetFortinet FortiOSFortiOS before 7.0.1—No fix listedCNA
  • Fortinet FortiOS VendorFortinet Affected FortiOS before 7.0.1 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*before 6.2.10; 6.4.0 to before 6.4.7VulnerableFortinet
cpe:2.3:o:fortinet:fortios:7.0.0:*:*:*:*:*:*:*7.0.0VulnerableFortinet
  • cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* Versions before 6.2.10; 6.4.0 to before 6.4.7 Vulnerable ·Fortinet
  • cpe:2.3:o:fortinet:fortios:7.0.0:*:*:*:*:*:*:* Versions 7.0.0 Vulnerable ·Fortinet

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-24018
  2. 2026-10-03 Alias added: GHSA-q8x9-vj32-mh5w

References

Advisory 1

  • TI-2026-20057 Authentication bypass in Fortinet FortiWeb KEVCVSS 3.1CRITICAL 9.4
  • TI-2025-18911 Heap-based buffer overflow in Fortinet FortiSwitchManager KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-36904 Authentication bypass in Fortinet FortiOS KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-15234 A use of externally-controlled format string in Fortinet FortiOS versions 7.4.0 through… KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-14448 Out-of-bounds write in Fortinet FortiOS KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-12585 Heap-based buffer overflow in Fortinet FortiOS-6K7K KEVCVSS 3.1CRITICAL 9.8
See all 276 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences