CVE-2021-26090 : What You Need to Know

This article provides details about CVE-2021-26090, a vulnerability found in Fortinet FortiMail versions 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6 that could allow an attacker to exhaust available memory via crafted login requests.

Understanding CVE-2021-26090

CVE-2021-26090 is a memory release vulnerability in the Webmail component of Fortinet FortiMail versions 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6. This vulnerability could be exploited by an unauthenticated remote attacker to consume available memory resources.

What is CVE-2021-26090?

The vulnerability in Fortinet FortiMail Webmail versions 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6 allows a remote attacker to exhaust memory by sending specially crafted login requests. This could lead to a denial-of-service condition on the affected system.

The Impact of CVE-2021-26090

With a CVSS base score of 5.3, this vulnerability poses a medium severity risk. An attacker could exploit this flaw to disrupt system availability by depleting memory resources through malicious login requests.

Technical Details of CVE-2021-26090

This section delves into specific technical information related to CVE-2021-26090.

Vulnerability Description

The vulnerability involves a failure to release memory after its effective lifetime in the Webmail component of Fortinet FortiMail, versions 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6. This oversight could be leveraged by a remote attacker to exhaust available memory.

Affected Systems and Versions

Fortinet FortiMail versions affected by this vulnerability include 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6. Users of these versions should take immediate action to mitigate the risk of exploitation.

Exploitation Mechanism

An unauthenticated remote attacker can exploit this vulnerability by sending specifically crafted login requests to the Fortinet FortiMail Webmail component. By causing the system to mishandle memory, the attacker can trigger a denial-of-service condition.

Mitigation and Prevention

To address CVE-2021-26090 and enhance system security, consider the following mitigation strategies.

Immediate Steps to Take

Update Fortinet FortiMail to the latest patched version to eliminate the vulnerability.
Monitor system resources for any unusual behavior that may indicate a memory exhaustion attack.

Long-Term Security Practices

Regularly apply security updates and patches to Fortinet FortiMail to protect against known vulnerabilities.
Implement network segmentation and access controls to restrict unauthorized access to critical systems.

Patching and Updates

Stay informed about security advisories from Fortinet and promptly apply recommended patches to address vulnerabilities and strengthen system defenses.