Read the docs
TI-2021-06337 Aliases CVE-2021-24020GHSA-8wr8-gr7j-v6cg

Improper signature verification in Fortinet FortiMail

Priority MEDIUM 44CWE-347Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
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-347.

Summary

A missing cryptographic step in the implementation of the hash digest algorithm in FortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7 may allow an unauthenticated attacker to tamper with signed URLs by appending further data which allows bypass of signature verification.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00616 49th 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
Total

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 FortiMailFortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7—No fix listedCNA
  • Fortinet FortiMail VendorFortinet Affected FortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*6.2.0 – 6.2.7; 6.4.0 to before 6.4.5VulnerableFortinet
  • cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:* Versions 6.2.0 – 6.2.7; 6.4.0 to before 6.4.5 Vulnerable ·Fortinet

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-24020
  2. 2026-10-03 Alias added: GHSA-8wr8-gr7j-v6cg

References

Advisory 1

  • TI-2026-65779 Path traversal in Fortinet FortiMail KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-23811 Stack-based buffer overflow in Fortinet FortiNDR KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-07433 Improper authentication in Fortinet FortiMail CVSS 3.1CRITICAL 9.8
  • TI-2021-14584 An improper authentication vulnerability in FortiMail before 7.0.1 may allow a remote… CVSS 3.1CRITICAL 9.8
  • TI-2021-06324 SQL injection in Fortinet FortiMail CVSS 3.1CRITICAL 9.8
  • TI-2023-25708 Improper access control in Fortinet FortiMail CVSS 3.1CRITICAL 9.0
See all 46 →

Sources

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