CVE-2021-39926 Explained : Impact and Mitigation

CVE-2021-39926, assigned by GitLab, involves a buffer overflow in the Bluetooth HCI_ISO dissector in Wireshark versions 3.4.0 to 3.4.9, potentially leading to denial of service through packet injection or crafted capture files.

Understanding CVE-2021-39926

This section provides insights into the nature and implications of CVE-2021-39926.

What is CVE-2021-39926?

CVE-2021-39926 describes a buffer overflow vulnerability existing in Wireshark versions 3.4.0 to 3.4.9 due to inadequate input size validation. Attackers can exploit this flaw to trigger denial of service via packet injection or manipulated capture files.

The Impact of CVE-2021-39926

The vulnerability poses a significant threat with a CVSS v3.1 base score of 7.5, categorizing it as a high severity issue. It allows unauthenticated attackers to disrupt service availability on affected systems.

Technical Details of CVE-2021-39926

This section delves into the technical aspects of CVE-2021-39926.

Vulnerability Description

The vulnerability involves a buffer overflow in the Bluetooth HCI_ISO dissector in Wireshark versions 3.4.0 to 3.4.9, facilitating denial of service attacks through packet injection or tampered capture files.

Affected Systems and Versions

Vendor: Wireshark Foundation
Affected Product: Wireshark
Vulnerable Versions: >=3.4.0, <3.4.10

Exploitation Mechanism

The vulnerability can be exploited by sending specially crafted packets or files to the vulnerable Wireshark instances, triggering buffer overflow and subsequently causing denial of service.

Mitigation and Prevention

In this section, essential steps to mitigate and prevent exploitation of CVE-2021-39926 are outlined.

Immediate Steps to Take

Update Wireshark to version 3.4.10 or above to eliminate the vulnerability.
Monitor network traffic for any signs of exploitation attempts.

Long-Term Security Practices

Conduct regular security audits and vulnerability assessments on network infrastructure.
Implement network segmentation to contain potential threats and limit their impact.
Train employees on identifying and reporting suspicious network activities.

Patching and Updates

Regularly apply security patches and updates to all software and systems to address known vulnerabilities and enhance overall security posture.