CVE-2021-3177

Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in _ctypes/callproc.c, which may lead to remote code execution in certain Python applications that accept floating-point numbers as untrusted input, as demonstrated by a 1e300 argument to c_double.from_param. This occurs because sprintf is used unsafely.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
python2.7	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 2.7.18-1~20.04.1
	18.04 LTS bionic	Fixed 2.7.17-1~18.04ubuntu1.6
	16.04 LTS xenial	Fixed 2.7.12-1ubuntu0~16.04.18
	14.04 LTS trusty	Fixed 2.7.6-8ubuntu0.6+esm10
python3.4	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Fixed 3.4.3-1ubuntu1~14.04.7+esm10
python3.5	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Fixed 3.5.2-2ubuntu0~16.04.13
	14.04 LTS trusty	Fixed 3.5.2-2ubuntu0~16.04.4~14.04.1+esm1
python3.6	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Fixed 3.6.9-1~18.04ubuntu1.4
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
python3.7	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Fixed 3.7.5-2~18.04.4
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
python3.8	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not in release
	21.04 hirsute	Not in release
	20.10 groovy	Fixed 3.8.6-1ubuntu0.2
	20.04 LTS focal	Fixed 3.8.5-1~20.04.2
	18.04 LTS bionic	Fixed 3.8.0-3~18.04.1
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
python3.9	24.10 oracular	Not in release
	24.04 LTS noble	Not in release
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Not in release
	22.04 LTS jammy	Not in release
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Fixed 3.9.5-3~20.10.1
	20.04 LTS focal	Fixed 3.9.5-3~20.04.1
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release

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Notes

mdeslaur

on Ubuntu, binaries are compiled with Fortify Source, so exploiting this issue will likely only cause Python to crash, leading to a denial of service.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
python3.6	Upstream: 34df10a
python3.7	Upstream: d9b8f13
python3.8	Upstream: ece5dfd
python3.9	Upstream: c347cbe

Severity score breakdown

Parameter	Value
Base score	9.8 · Critical
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

USN-4754-1
Python vulnerabilities
25 February 2021

USN-4754-4
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3 March 2021

USN-4754-3
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12 March 2021

USN-4754-5
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8 February 2022

USN-6891-1
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11 July 2024

Cvss 3 Severity Score