Name: CVE-2021-40839: Loop with Unreachable Exit Condition
Creator: Rapid7
Published: 2021-09-10T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2021-40839, CWE-835, CVSS 7.5, EPSS 0.0552

The rencode package through 1.0.6 for Python allows an infinite loop in typecode decoding (such as via ;\x2f\x7f), enabling a remote attack that consumes CPU and memory.

CVSS Details

CVSS 3.1 Base Score: 7.5
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alpine Linux	—	Upgrade py3-rencode	Aug 22, 2024	Sep 10, 2021
Arch Linux	—	Upgrade to the latest version of Arch Linux	Jul 11, 2025	Sep 10, 2021
Debian	—	Upgrade python-rencode	Jul 30, 2024	Sep 10, 2021
Freebsd	—	Upgrade py39-rencode	Apr 14, 2023	Mar 25, 2023

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CVSS Details

Covered by Rapid7

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