TI-2021-08053 Aliases CVE-2021-26103 GHSA-wp9j-fhh7-35qv

Insufficient verification of data authenticity in Fortinet FortiOS

LOW 38CWE-345Published 2021-12-08 · Updated 2024-10-25

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Security bypass
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-345.

Summary

An insufficient verification of data authenticity vulnerability (CWE-345) in the user interface of FortiProxy verison 2.0.3 and below, 1.2.11 and below and FortiGate verison 7.0.0, 6.4.6 and below, 6.2.9 and below of SSL VPN portal may allow a remote, unauthenticated attacker to conduct a cross-site request forgery (CSRF) attack . Only SSL VPN in web mode or full mode are impacted by this vulnerability.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00436 38th 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

Vendor	Product	Affected versions	Fixed in	Status	Source
Fortinet	Fortinet FortiOS	FortiOS 7.0.0, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.6.14, 5.6.13, 5.6.12, 5.6.11, 5.6.10, 5.6.9, 5.6.8, 5.6.7, 5.6.6, 5.6.5, 5.6.4, 5.6.3, 5.6.2, 5.6.1, 5.6.0	—	No fix listed	CNA

Fortinet FortiOS VendorFortinet Affected FortiOS 7.0.0, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 6.0.10, 6.0.9, 6.0.8, 6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.1, 6.0.0, 5.6.14, 5.6.13, 5.6.12, 5.6.11, 5.6.10, 5.6.9, 5.6.8, 5.6.7, 5.6.6, 5.6.5, 5.6.4, 5.6.3, 5.6.2, 5.6.1, 5.6.0 Fixed in — No fix listed CNA

CPE configurations NVD · 3

CPE	Versions	Role	Vendor
cpe:2.3:a:fortinet:fortiproxy::::::::	1.2.0 – 1.2.11; 2.0.0 – 2.0.3	Vulnerable	Fortinet
cpe:2.3:o:fortinet:fortios::::::::	5.6.0 – 5.6.14; 6.0.0 – 6.0.13; 6.2.0 – 6.2.9; 6.4.0 – 6.4.6	Vulnerable	Fortinet
cpe:2.3:o:fortinet:fortios:7.0.0:::::::*	7.0.0	Vulnerable	Fortinet

cpe:2.3:a:fortinet:fortiproxy:*:*:*:*:*:*:*:* Versions 1.2.0 – 1.2.11; 2.0.0 – 2.0.3 Vulnerable ·Fortinet
cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* Versions 5.6.0 – 5.6.14; 6.0.0 – 6.0.13; 6.2.0 – 6.2.9; 6.4.0 – 6.4.6 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

2026-10-02 Threatist record created from CVE-2021-26103
2026-10-03 Alias added: GHSA-wp9j-fhh7-35qv

References

Patch 1

https://fortiguard.com/advisory/FG-IR-20-158

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