Improper signature verification in Fortinet FortiMail
Priority LOW 33CWE-347Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- 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 Identity-Based Encryption service of FortiMail before 7.0.0 may allow an unauthenticated attacker who intercepts the encrypted messages to manipulate them in such a way that makes the tampering and the recovery of the plaintexts possible.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00342 27th 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
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-26100
- 2026-10-03 Alias added: GHSA-j84j-6h2f-jqj3
References
More Fortinet Fortimail vulnerabilities
- 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
Sources
- CVE-2021-26100 · CVE Program
- CVE-2021-26100 · NVD
- FIRST EPSS
- GHSA-j84j-6h2f-jqj3 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences