CVE-2021-26076 Explained : Impact and Mitigation

The jira.editor.user.mode cookie set by the Jira Editor Plugin in Jira Server and Data Center has a security misconfiguration vulnerability. Attackers could learn the user's editing mode.

Understanding CVE-2021-26076

This CVE describes a vulnerability in the Jira Editor Plugin used in Jira Server and Data Center, which could be exploited by remote attackers.

What is CVE-2021-26076?

The jira.editor.user.mode cookie in Jira Server and Data Center allows attackers to determine a user's editing mode via an attacker-in-the-middle attack.

The Impact of CVE-2021-26076

Remote anonymous attackers can exploit this vulnerability to discern which editing mode a user is in, compromising user privacy and potentially leading to further attacks.

Technical Details of CVE-2021-26076

The vulnerability arises due to a security misconfiguration in the Jira Editor Plugin.

Vulnerability Description

The jira.editor.user.mode cookie lacks a secure attribute, enabling attackers to conduct attacks.

Affected Systems and Versions

Affected versions of Jira Server include those before 8.5.12, between 8.6.0 and 8.13.4, and before 8.15.0.
Affected versions of Jira Data Center mirror those of Jira Server.

Exploitation Mechanism

Attackers use the lack of a secure attribute in the cookie to perform a man-in-the-middle attack and determine a user's editing mode.

Mitigation and Prevention

To address CVE-2021-26076, it is essential to take immediate steps and implement long-term security practices.

Immediate Steps to Take

Update Jira Server and Data Center to versions beyond the specified vulnerable ranges.
Ensure secure https configuration for Jira instances.

Long-Term Security Practices

Regularly update Jira software to the latest versions.
Implement security best practices to safeguard against similar vulnerabilities.

Patching and Updates

Keep track of security advisories from Atlassian and promptly apply patches and updates to mitigate known vulnerabilities.