CVE-2026-55195

Description

A flaw was found in py7zr, a Python library for 7zip archive handling. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by providing a specially crafted .7z file. The Worker.decompress() function fails to track the total decompressed size, enabling a small archive to expand significantly and exhaust system resources such as disk space or memory during extraction. This issue is also known as a decompression bomb (CWE-409).

Statement

This Moderate impact flaw in the py7zr Python library can lead to a denial of service when processing specially crafted 7zip archives. An attacker could provide a malicious archive that, upon decompression, exhausts system resources such as disk space or memory, impacting the availability of services that utilize py7zr for archive handling.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Understanding the Weakness (CWE)

CWE-409

Availability

Technical Impact: DoS: Amplification; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)

System resources, CPU and memory, can be quickly consumed. This can lead to poor system performance or system crash.

Frequently Asked Questions

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