FortiMail
CVE-2021-26091: Use of a cryptographically weak pseudo-random number generator in FortiMail
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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| FortiMail 6.4.0 to 6.4.4 | 6.4.5 or later |
| FortiMail 6.2.0 to 6.2.9 | Upgrade past 6.2.9; see the advisory |
| FortiMail 6.2 | 6.2.* or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 10 Oct 2026.