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Advisory severityMedium6.5Red Hat Linux

Medium [CVE-2026-55195] Denial of Service via decompression bomb in 7zip archive extraction

This medium-severity Red Hat Linux advisory covers CVE-2026-55195.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-55195 Source published Source updated

VulniPulse record published Record updated

CVE-2026-55195
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

Summary

py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption.

Prior to 1.1.3, py7zr's Worker.decompress() extracted archive entries without tracking total decompressed size, allowing a crafted.7z file such as a 15.6 KB archive that expands to 100 MB to exhaust disk or memory before extraction completes. This issue is fixed in version 1.1.3.

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). 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. Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

Weakness: CWE-409.

Is CVE-2026-55195 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-55195 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-55195?

Upgrade to a fixed release named by Red Hat:

  • 1.1.3

Confirm against the vendor advisory before you patch.

Affected versions
  • < 1.1.3
  • < 15.6

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

Fixed versions
  • 1.1.3

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

Mitigation checklist

Recommended fix / 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.

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

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