CVE-2026-55195

HIGH

py7zr: Decompression bomb (zip bomb) denial of service via unchecked extraction size

Title source: cna

Description

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.

References (3)

Core 3

Core References

X_Refsource_Misc x_refsource_misc

https://github.com/miurahr/py7zr/releases/tag/v1.1.3

X_Refsource_Confirm x_refsource_confirm

https://github.com/miurahr/py7zr/security/advisories/GHSA-gjrg-mpp7-g774

X_Refsource_Misc x_refsource_misc

https://github.com/miurahr/py7zr/commit/28faf107b64374fa5a02bfb93aa2024e281ca97b

View Writeup ZIP pw:eip

Scores

CVSS v4 8.7

EPSS 0.0032

EPSS Percentile 24.2%

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment

Exploitation poc

Automatable yes

Technical Impact partial

Details

CWE

CWE-409

Status published

Products (1)

miurahr/py7zr < 1.1.3

Published Jul 08, 2026

Tracked Since Jul 09, 2026