CVE Vulnerabilities

CVE-2021-3737

Loop with Unreachable Exit Condition ('Infinite Loop')

Published: Mar 04, 2022 | Modified: Dec 17, 2025
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
7.1 HIGH
AV:N/AC:M/Au:N/C:N/I:N/A:C
RedHat/V2
RedHat/V3
6.5 LOW
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM
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A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite loop, consuming CPU time. The highest threat from this vulnerability is to system availability.

Weakness

The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

Affected Software

NameVendorStart VersionEnd Version
PythonPython3.6.0 (including)3.6.14 (excluding)
PythonPython3.7.0 (including)3.7.11 (excluding)
PythonPython3.8.0 (including)3.8.11 (excluding)
PythonPython3.9.0 (including)3.9.6 (excluding)
Red Hat Enterprise Linux 8RedHatpython39:3.9-8050020210811100211.d428a79b*
Red Hat Enterprise Linux 8RedHatpython39-devel:3.9-8050020210811100211.d428a79b*
Red Hat Enterprise Linux 8RedHatpython38:3.8-8060020220120164031.5294be16*
Red Hat Enterprise Linux 8RedHatpython38-devel:3.8-8060020220120164031.5294be16*
Red Hat Enterprise Linux 8RedHatpython27:2.7-8060020220210185952.8cdc2268*
Red Hat Enterprise Linux 8RedHatpython3-0:3.6.8-45.el8*
Red Hat Enterprise Linux 8RedHatpython3-0:3.6.8-45.el8*
Red Hat Software Collections for Red Hat Enterprise Linux 7RedHatpython27-python-0:2.7.18-4.el7*
Python3.10Ubuntuhirsute*
Python3.10Ubuntutrusty*
Python3.10Ubuntuxenial*
Python3.4Ubuntuesm-infra-legacy/trusty*
Python3.4Ubuntutrusty*
Python3.4Ubuntutrusty/esm*
Python3.4Ubuntuxenial*
Python3.5Ubuntuesm-infra-legacy/trusty*
Python3.5Ubuntuesm-infra/xenial*
Python3.5Ubuntutrusty*
Python3.5Ubuntutrusty/esm*
Python3.5Ubuntuxenial*
Python3.6Ubuntubionic*
Python3.6Ubuntuesm-infra/bionic*
Python3.6Ubuntutrusty*
Python3.6Ubuntuxenial*
Python3.7Ubuntubionic*
Python3.7Ubuntuesm-apps/bionic*
Python3.7Ubuntutrusty*
Python3.7Ubuntuxenial*
Python3.8Ubuntubionic*
Python3.8Ubuntuesm-apps/bionic*
Python3.8Ubuntuesm-infra/focal*
Python3.8Ubuntufocal*
Python3.8Ubuntutrusty*
Python3.8Ubuntuxenial*
Python3.9Ubuntuesm-apps/focal*
Python3.9Ubuntufocal*
Python3.9Ubuntuhirsute*
Python3.9Ubuntutrusty*
Python3.9Ubuntuxenial*

References