Module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check’

This attributeerror: module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check’ error message happens when you are working with Python and OpenSSL.

Module 'lib' has no attribute 'x509_v_flag_cb_issuer_check'

This error usually happens when the x509_v_flag_cb_issuer_check attribute is missing from the OpenSSL library.

If you’re struggling to fix this error attributeerror: module lib has no attribute x509_v_flag_cb_issuer_check, don’t worry, you have this article.

In this article, we’ll discuss the solutions and important details that you need to know.

What is the “x509_v_flag_cb_issuer_check” attribute?

The x509_v_flag_cb_issuer_check is an attribute that refers to a flag used in OpenSSL, a popular open-source cryptographic library, which is used for verifying X.509 digital certificates.

Specifically, it is used to enable or disable the check for matching certificate issuers. Also, it provides tools for SSL/TLS encryption.

What is “attributeerror: module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check'” error?

The “attributeerror: module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check‘” is a Python error that happens when your code is trying to access an attribute called “x509_v_flag_cb_issuer_check in a module called “lib.”

However, this attribute wasn’t found or doesn’t exist in that module. This error occurs for various reasons:

  • If you made a typo in the attribute name or if you are using an outdated version of the ‘lib’ module that doesn’t have this attribute.
  • Missing dependency that is required for the module to function properly.
  • It’s also possible that the module or library is not properly installed or configured.
  • The OpenSSL version being used is not compatible with the code being executed.

In order to resolve this error “module lib has no attribute x509_v_flag_cb_issuer_check“. You have to check the import statement, verify that the module is installed correctly, and ensure that the attribute name is correct.

It’s also helpful to look for any related error messages or log files that may provide more information about the issue.

Solutions for “attributeerror: module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check'” error?

The following are effective solutions you may use to fix the error that you are facing right now.

Solution 1: Upgrade OpenSSL

To resolve thispython attributeerror: module lib has no attribute x509_v_flag_cb_issuer_check” error. You can try updating OpenSSL and to its latest version and ensuring that it is installed correctly.

pip install pyOpenSSL –upgrade


pip3 install pyOpenSSL –upgrade

After upgrading the OpenSSL then the error still exist, you can try to upgrade pip, using the following command:

python -m pip install –upgrade pip


pip install –upgrade pip

If the error still persists, you can also try to examine the code where this error is occurring to see if there are any issues with how the ‘lib’ module is being imported or used.

Alternatively, you can try using a different version of OpenSSL that is known to be compatible with your code.

For instance:

pip3 installpyOpenSSL==20.0.1

Solution 2: Reinstall the Python OpenSSL package

If upgrading the package doesn’t solve the issue you can reinstall the Python OpenSSL package. This can be done using the following commands:

To uninstall:

pip3 uninstall pyOpenSSL

To reinstall:

pip3 install pyOpenSSL

Solution 3: If you are using Ubuntu

If you are using Ubuntu, the following commands will get rid of the error:

sudo pip3 install pyOpenSSL --upgrade
sudo pip3 install cryptography --upgrade

If the error still exists, you can try to use the following commands:

sudo apt remove python3-pip 
sudo python3

After that, execute these commands:

sudo pip3 install pyopenssl

sudo pip3 install pyopenssl –upgrade

Solution 4: Downgrading cryptography library

If you’ve done the possible solutions above yet the error still exist, try to downgrade the cryptography library.

For example:

pip install cryptography==36.0.0

You can also try this method below:

pip uninstall cryptography

pip install –upgrade cryptography==36.0.2

Note: The version of cryptography should be compatible with the pyOpenSSL version.

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Now you can easily fix the error because this article provides solutions for the attributeerror: module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check‘“, which is a big help in solving the problem you are currently facing.

We are really hoping that this article will totally help you troubleshoot this “module ‘lib’ has no attribute ‘x509_v_flag_cb_issuer_check‘” error.

Thank you very much for reading to the end of this article. Just in case you have more questions or inquiries, feel free to comment, and you can also visit our website for additional information.

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