CVE-2020-36242

CRITICAL9.1EPSS 1.6%

PyCA Cryptography symmetrically encrypting large values can lead to integer overflow

Published: 2/10/2021Modified: 12/3/2025

Also known as:ALPINE-CVE-2020-36242

Description

In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.

Affected packages (4)

Alpine/py3-cryptographyfrom 0, < 3.3.2-r0
Debian/python-cryptographyfrom 0, < 3.3.2-1
PyPI/cryptography>= 3.1, < 3.3.2
PyPI/cryptography>= 3.1, < 3.3.2

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 4.0	—	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N
osv	CVSS 3.1	CRITICAL9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

References (16)

ADVISORYhttps://github.com/advisories/GHSA-rhm9-p9w5-fwm7
ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2020-36242
ADVISORYhttps://security.alpinelinux.org/vuln/CVE-2020-36242
ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2020-36242
PATCHhttps://github.com/pyca/cryptography
WEBhttps://github.com/pyca/cryptography/blob/master/CHANGELOG.rst
WEBhttps://github.com/pyca/cryptography/commit/82b6ce28389f0a317bc55ba2091a74b346db7cae
WEBhttps://github.com/pyca/cryptography/compare/3.3.1...3.3.2
WEBhttps://github.com/pyca/cryptography/issues/5615
WEBhttps://github.com/pyca/cryptography/security/advisories/GHSA-rhm9-p9w5-fwm7
WEBhttps://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2021-63.yaml
WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L7RGQLK4J5ZQFRLKCHVVG6BKZTUQMG7E
WEBhttps://lists.fedoraproject.org/archives/list/[email protected]/message/L7RGQLK4J5ZQFRLKCHVVG6BKZTUQMG7E
WEBhttps://lists.fedoraproject.org/archives/list/[email protected]/message/L7RGQLK4J5ZQFRLKCHVVG6BKZTUQMG7E/
WEBhttps://www.oracle.com/security-alerts/cpuapr2022.html
WEBhttps://www.oracle.com/security-alerts/cpujul2022.html