CVE-2018-7548 : Security Advisory and Response

A NULL pointer dereference vulnerability in zsh versions up to 5.4.2 can lead to exploitation when certain expressions are used on empty array results.

Understanding CVE-2018-7548

This CVE involves a vulnerability in zsh versions up to 5.4.2 that can result in a NULL pointer dereference under specific conditions.

What is CVE-2018-7548?

In zsh through version 5.4.2, a NULL pointer dereference occurs when utilizing specific expressions on empty array results.

The Impact of CVE-2018-7548

The vulnerability can be exploited to cause a NULL pointer dereference, potentially leading to a denial of service condition or other impacts on affected systems.

Technical Details of CVE-2018-7548

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability exists in the subst.c file of zsh versions up to 5.4.2, triggered when certain expressions are applied to empty array results.

Affected Systems and Versions

Affected versions: zsh up to 5.4.2
Specific products and vendors are not applicable in this context.

Exploitation Mechanism

Exploitation of this vulnerability involves utilizing the ${(PA)...} expression on an empty array result in zsh versions up to 5.4.2.

Mitigation and Prevention

Protecting systems from CVE-2018-7548 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update zsh to a version beyond 5.4.2 to mitigate the vulnerability.
Avoid using the ${(PA)...} expression on empty array results.

Long-Term Security Practices

Regularly update software to the latest versions to address known vulnerabilities.
Implement secure coding practices to prevent NULL pointer dereference issues.

Patching and Updates

Apply patches provided by zsh to fix the vulnerability.