CVE-2021-26091

Published Mar 24, 2025 CVSS 3.1 · 6.9 Medium EPSS < 1% KEV · Not listed

Description

A use of a cryptographically weak pseudo-random number generator vulnerability in the authenticator of the Identity Based Encryption service of FortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7 may allow an unauthenticated attacker to infer parts of users authentication tokens and reset their credentials.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Fortinet

FortiMail

unaffected

Version	Status	Constraints
`6.4.0`	affected	≤ 6.4.4
`6.2.0`	affected	≤ 6.2.9
`6.2.0`	affected	< 6.2.*

Configuration 1 [-]

cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*

No data.

No data available yet.

Remediation

Vendor Solution

Please upgrade to FortiMail version 7.0.0 or above Please upgrade to FortiMail version 6.4.5 or above

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2021-12912	A use of a cryptographically weak pseudo-random number generator vulnerability in the authenticator of the Identity Based Encryption service of FortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7 may allow an unauthenticated attacker to infer parts of users authentication tokens and reset their credentials.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.308% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://fortiguard.com/advisory/FG-IR-21-031

History

Jul 23, 2025 4:00 PM Affected versions updated View changes

Type	Values Removed	Values Added
CPEs		cpe:2.3:a:fortinet:fortimail::::::::

Mar 31, 2025 7:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Mar 24, 2025 3:45 PM Description updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A use of a cryptographically weak pseudo-random number generator vulnerability in the authenticator of the Identity Based Encryption service of FortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7 may allow an unauthenticated attacker to infer parts of users authentication tokens and reset their credentials.
First Time appeared		Fortinet Fortinet fortimail
Weaknesses		CWE-338
CPEs		cpe:2.3:a:fortinet:fortimail:6.2.::::::: cpe:2.3:a:fortinet:fortimail:6.2.0:::::::* cpe:2.3:a:fortinet:fortimail:6.2.1:::::::* cpe:2.3:a:fortinet:fortimail:6.2.2:::::::* cpe:2.3:a:fortinet:fortimail:6.2.3:::::::* cpe:2.3:a:fortinet:fortimail:6.2.4:::::::* cpe:2.3:a:fortinet:fortimail:6.2.5:::::::* cpe:2.3:a:fortinet:fortimail:6.2.6:::::::* cpe:2.3:a:fortinet:fortimail:6.2.7:::::::* cpe:2.3:a:fortinet:fortimail:6.2.8:::::::* cpe:2.3:a:fortinet:fortimail:6.2.9:::::::* cpe:2.3:a:fortinet:fortimail:6.4.0:::::::* cpe:2.3:a:fortinet:fortimail:6.4.1:::::::* cpe:2.3:a:fortinet:fortimail:6.4.2:::::::* cpe:2.3:a:fortinet:fortimail:6.4.3:::::::* cpe:2.3:a:fortinet:fortimail:6.4.4:::::::*
Vendors & Products		Fortinet Fortinet fortimail
References		https://fortiguard.com/advisory/FG-IR-21-031
Metrics		cvssV3_1 `{'score': 6.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:U/RC:C'}`