CVE-2023-40890

Vulnerability

A stack-based buffer overflow vulnerability exists in the lookup_sequence function of ZBar version 0.23.90. This flaw can be triggered by a specially crafted QR code, either input digitally or physically scanned by a vulnerable scanner. The issue lies in how the function handles certain malformed data, allowing an overflow on the stack. [1]

Exploitation

An attacker can exploit this vulnerability by providing a malicious QR code to a user or system using ZBar 0.23.90. The QR code can be submitted digitally (e.g., as an image file) or prepared for physical scanning. No special privileges are required; the exploit occurs during normal processing of the QR code by the vulnerable software. The precise sequence of steps involves crafting a QR code that triggers the overflow in lookup_sequence, leading to memory corruption. [1]

Impact

Successful exploitation could result in information disclosure (e.g., reading sensitive memory contents) or arbitrary code execution. In the latter case, the attacker may gain control of the affected process, potentially leading to full system compromise depending on the context (e.g., a scanning kiosk or server-side barcode processing). The exact privilege level achieved is not specified in the available references. [1]

Mitigation

As of the available references, no official fix or patched version for ZBar 0.23.90 has been disclosed. Users should monitor the ZBar project for updates. No workarounds are provided in the references. The CVE is not listed on CISA's Known Exploited Vulnerabilities (KEV) catalog at the time of writing. [1]