What is the severity of CVE-2021-26091?

CVE-2021-26091 has been classified as a high severity vulnerability due to its potential to allow unauthenticated attackers to compromise user authentication.

How do I fix CVE-2021-26091?

To fix CVE-2021-26091, update FortiMail to version 6.4.5 or later, or 6.2.8 or later to mitigate the vulnerability.

Who is affected by CVE-2021-26091?

CVE-2021-26091 affects users of FortiMail versions 6.4.0 to 6.4.4 and 6.2.0 to 6.2.7.

What are the potential impacts of CVE-2021-26091?

The potential impacts of CVE-2021-26091 include the ability for attackers to infer authentication tokens, leading to unauthorized access.

Is there a workaround for CVE-2021-26091?

There is no official workaround for CVE-2021-26091; users are advised to upgrade to the patched versions.

Vulnerability/
CVE-2021-26091

high

7.5

CWE

338

24/3/2025

31/3/2025

CVE-2021-26091: Weak RNG

First published: Mon Mar 24 2025(Updated: )

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.

Credit: psirt@fortinet.com

Affected Software	Affected Version	How to fix
Fortinet Fortimail-200d	>=6.4.0<=6.4.4>=6.2.0<=6.2.7

Remedy

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

Never miss a vulnerability like this again

Reference Links

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

Frequently Asked Questions

What is the severity of CVE-2021-26091?
CVE-2021-26091 has been classified as a high severity vulnerability due to its potential to allow unauthenticated attackers to compromise user authentication.
How do I fix CVE-2021-26091?
To fix CVE-2021-26091, update FortiMail to version 6.4.5 or later, or 6.2.8 or later to mitigate the vulnerability.
Who is affected by CVE-2021-26091?
CVE-2021-26091 affects users of FortiMail versions 6.4.0 to 6.4.4 and 6.2.0 to 6.2.7.
What are the potential impacts of CVE-2021-26091?
The potential impacts of CVE-2021-26091 include the ability for attackers to infer authentication tokens, leading to unauthorized access.
Is there a workaround for CVE-2021-26091?
There is no official workaround for CVE-2021-26091; users are advised to upgrade to the patched versions.

collector/mitre-cve
source/MITRE
collector/nvd-api
source/NVD
agent/remedy
agent/weakness
agent/references
agent/description
agent/first-publish-date
agent/type
agent/last-modified-date
agent/severity
agent/author
agent/source
agent/event
agent/softwarecombine
agent/tags
agent/guess-ai
agent/software-canonical-lookup
vendor/fortinet
canonical/fortinet fortimail-200d

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