Python up to 3.9.1 _ctypes/callproc.c PyCArg_repr c_double.from_param buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.4$0-$5k0.00

Summaryinfo

A vulnerability was found in Python up to 3.9.1 and classified as critical. This affects the function PyCArg_repr of the file _ctypes/callproc.c. Executing a manipulation of the argument c_double.from_param can lead to buffer overflow. This vulnerability appears as CVE-2021-3177. The attack may be performed from remote. There is no available exploit. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability has been found in Python up to 3.9.1 (Programming Language Software) and classified as critical. This vulnerability affects the function PyCArg_repr of the file _ctypes/callproc.c. The manipulation of the argument c_double.from_param with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was presented 01/19/2021. The advisory is shared for download at python-security.readthedocs.io. This vulnerability was named CVE-2021-3177. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 236633 (Alibaba Cloud Linux 3 : 0112: python27:2.7 (ALINUX3-SA-2022:0112)), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (236633). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 236633
Nessus Name: Alibaba Cloud Linux 3 : 0112: python27:2.7 (ALINUX3-SA-2022:0112)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: github.com

Timelineinfo

01/19/2021 🔍
01/19/2021 +0 days 🔍
01/19/2021 +0 days 🔍
12/18/2025 +1794 days 🔍

Sourcesinfo

Advisory: python-security.readthedocs.io
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-3177 (🔍)
GCVE (CVE): GCVE-0-2021-3177
GCVE (VulDB): GCVE-100-168088

Entryinfo

Created: 01/19/2021 14:24
Updated: 12/18/2025 16:32
Changes: 01/19/2021 14:24 (41), 02/15/2021 09:42 (2), 02/15/2021 09:46 (18), 05/19/2025 19:40 (22), 12/18/2025 16:32 (2)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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