Python security insights

How secure is the Python ecosystem? Based on millions of scans performed by Snyk, this report analyzes the security of Python projects. Read this report to learn about common security issues and trends.

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The security footprint of Python projects

47% of Python projects are vulnerable

An average Python project has around 35 dependencies. Out of these, 17 are direct dependencies and 18 are indirect dependencies.

In 47% of these projects, dependencies are introducing vulnerabilities. An average vulnerable project consists of 33 known vulnerabilities, out of which 10% are critical severity vulnerabilities, 26% are high severity, 26% medium severity, and 38% low severity.

The good news – you can eliminate 87% of known vulnerabilities by upgrading the vulnerable package!

Snyk’s automated fix PRs will help you automatically find, prioritize and fix vulnerabilities in your Python dependencies.

Vulnerabilities in projects by severity


Common security issues in Python projectsCommon security issues in Python projects

OWASP top 10 found in the majority of Python projects

Snyk Code – Snyk’s Static Application Security Testing (SAST) solution – was trained using over 120K Python projects on GitHub. Over 60% of these projects were found to include issues on OWASP’s 2021 top 10 list with XSS (Cross Site Scripting) found in 20% of projects.

There are two issues specific to Python, though:

  • Unicode issues: Like most programming languages older than 10 years, Python has a history of issues related to handling encoding in strings.
  • Closing API calls: When interacting with external resources such as file or network streams, calling the close function signals the system to flush the content as well as to free any handles.

Snyk’s Python cheatsheet provides a list of typical issue types with concrete advice on how to tackle them.

Top 5 Python Issues Reported by Snyk Code

TLS Cert Disabled23%
Path Traversal23%
SQL Injection12%

Commonly downloaded Python packagesCommonly downloaded Python packages

Python packages are healthy!

What open source packages are Python developers using? How healthy are these projects? Are these packages secure? How are they included in projects?

To answer these questions we looked at two key datasets – the 1000 most downloaded packages from PyPI and the 1000 most common packages used in the Python projects monitored by Snyk.

To examine PyPI package downloads, we used Snyk Advisor – a free, online, research tool that helps you decide which open source packages or container base images to use to build your Python project. Containing all projects from PyPI, Snyk Advisor calculates a health score based on packages’ popularity, security, maintenance, and community strength.

For the 1000 most downloaded Python packages from PyPI, Snyk Advisor suggests an average high health score of 81%!

Package# of downloads*Health scoreLast release date**AgeLicenseContributorsDependencies
urllib3158,893,22898.50%Jun 25, 202112 yearsMIT2500
boto3134,136,17195.50%Jul 28, 20217 yearsApache-2.01106
six128,572,88886.93%May 5, 202111 yearsMIT600
botocore128,304,03297.00%Jul 27, 20219 yearsApache-2.01304
requests116,360,26297.00%Jul 13, 202110 yearsApache-2.04107
certifi113,424,29785.70%May 30, 202110 yearsMPL-2.0300
setuptools113,270,73395.64%Jul 19, 202115 yearsMIT3800
idna112,275,17083.60%May 29, 20218 yearsBSD-3-Clause200
chardet107,130,51988.43%Dec 10, 202015 yearsLGPL-2.1400
python-dateutil100,233,78894.14%Jul 14, 202113 yearsApache-2.0 OR BSD-2-Clause1101

* Average monthly downloads for the period of March 21-June 21.

** At the time of writing.

*** In the latest version.

The most vulnerable packages in Python projectsThe most vulnerable packages in Python projects

#1 downloaded package on PyPi is vulnerable

With millions of downloads a week, urllib3 is the most downloaded Python package on PyPI. It is also the 3rd most used package in the projects monitored by Snyk.

While the latest version of the package is safe to use, previous versions include security vulnerabilities, including high and medium severity issues. Version 1.24.3, downloaded over 2 million times a week, includes a high severity CRLF injection vulnerability. Version 1.26.3, downloaded over 1.5 million times a week contains an Improper Certificate Validation vulnerability.

PackageUseVulnerabilitiesMinimum known vuln free versionWeekly downloads
urllib3HTTP client Critical – 0
High – 3
Medium – 6
Low – 1
1.26.6 (latest)38M
pillowImaging libraryCritical – 1
High – 18
Medium – 7
Low –
8.3.1 (latest)8.3M
PyYAMLYAML parser and emitter Critical – 45.421M
ipaddressIPv4/IPv6 manipulation libraryCritical – 0
High – 1
Medium – 2
Low – 0
cryptographyCryptographic recipes and primitivesCritical – 0
High – 4
Medium – 3
Low – 0
djangoHigh-level Python Web frameworkCritical – 0
High – 8
Medium – 15
Low – 5
jinja2A fast and expressive template engineCritical – 0
High – 1
Medium – 4
Low – 5
pygmentsA syntax highlighting packageCritical -1
High – 2
Medium – 0
Low – 0
requestsHTTP client Critical -1
High – 0
Medium – 5
Low – 0
rsaRSA implementationCritical -0
High – 2
Medium – 3
Low – 0

Vulnerabilities in Python containersVulnerabilities in Python containers

Most container vulnerabilities can be fixed using slimmer images

While it’s pretty easy to get a Python app running in a container, as with so much in life the “easy way” isn’t always the best way. Containers come with pre-installed Linux packages, which may or may not be important to making your app run but will impact your vulnerability reports.

Popular Python base images vary in size and the number of vulnerabilities they introduce. “Fat” images like :3.9, :3.8, and :3.7 are the most common, despite all the best practices stating you should use a slimmer base image to reduce attack surface. You can get both worlds in containers through the use of multi-stage builds, starting with the bigger images to simplify building and testing your code and then moving the required production packages to a slim image in the final stage.

Python security insights

A word about this report

Snyk performs millions of monthly scans of hundreds of thousands of Python projects, providing us with the ability to describe what an average Python project looks like and give you an idea of what you might find when you scan one of your Python projects. The data used for this report was taken from the Snyk Intel Vulnerability Database, hundreds of thousands of Python projects monitored by Snyk, the same number of projects used as a training set for Snyk Code, and Snyk Advisor.

Download the full report

The vast majority of our survey respondents are still early in their Python adoption journey, so if you don’t think you’re in that top 7%, you’re not alone. Our full Python Security Insights report has more details on what’s holding people back, and what they’re doing today, and how they’d like to improve.

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