CVE-2019-19275 : What You Need to Know

A vulnerability in versions 1.3.0 and 1.3.1 of typed_ast could allow an attacker to crash a Python interpreter process by triggering an out-of-bounds read. This issue also impacted specific prereleases of Python 3.8.0-alpha.

Understanding CVE-2019-19275

This CVE involves a vulnerability in the typed_ast library that could lead to a denial-of-service attack on Python interpreters.

What is CVE-2019-19275?

The vulnerability in typed_ast versions 1.3.0 and 1.3.1 allows an attacker to crash a Python interpreter process by exploiting an out-of-bounds read in the ast_for_arguments function. This could be particularly risky in scenarios where Python code is parsed without execution, such as web-based services.

The Impact of CVE-2019-19275

The vulnerability poses a risk of crashing Python interpreter processes, potentially leading to denial-of-service conditions. Attackers could exploit this issue in environments that parse Python code without executing it, such as web services.

Technical Details of CVE-2019-19275

The technical aspects of the vulnerability in typed_ast versions 1.3.0 and 1.3.1.

Vulnerability Description

The vulnerability involves an out-of-bounds read in the ast_for_arguments function of typed_ast, which could be exploited to crash Python interpreter processes.

Affected Systems and Versions

typed_ast versions 1.3.0 and 1.3.1
Specific prereleases of Python 3.8.0-alpha

Exploitation Mechanism

Attackers with the ability to make a Python interpreter parse Python source code, without necessarily executing it, could trigger the vulnerability and crash the interpreter process.

Mitigation and Prevention

Steps to mitigate and prevent the CVE-2019-19275 vulnerability.

Immediate Steps to Take

Update typed_ast to a non-vulnerable version.
Monitor Python interpreter processes for unusual behavior.

Long-Term Security Practices

Regularly update Python libraries and dependencies.
Implement input validation and sanitization in web-based services.

Patching and Updates

Apply patches provided by the library maintainers.
Stay informed about security advisories and updates from Python.