python – urllib and “SSL: CERTIFICATE_VERIFY_FAILED” Error

The Question :

311 people think this question is useful

I am getting the following error:

Exception in thread Thread-3:
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 810, in        __bootstrap_inner
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 763, in  run
self.__target(*self.__args, **self.__kwargs)
File "/Users/Matthew/Desktop/Skypebot 2.0/", line 271, in process
info = urllib2.urlopen(req).read()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 154, in urlopen
return, data, timeout)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 431, in open
response = self._open(req, data)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 449, in _open
'_open', req)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 409, in _call_chain
result = func(*args)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 1240, in https_open
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 1197, in do_open
raise URLError(err)
URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:581)>

This is the code that is causing this error:

if input.startswith("!web"):
    input = input.replace("!web ", "")      
    url = "" + input
    req = urllib2.Request(url, headers={ 'X-Mashape-Key': 'XXXXXXXXXXXXXXXXXXXX' })
    info = urllib2.urlopen(req).read()
    Message.Chat.SendMessage ("" + info)

The API I’m using requires me to use HTTPS. How can I make it bypass the verification?

The Question Comments :
  • There is nothing wrong with the URL and it can be successfully verified with the common trusted certificates. So you should better not try to bypass certificate validation, but to fix it. Which version of python you are using?
  • This might be related to The server uses the same kind of certificate chain with multiple trust path. See there which cafile you might need to use for verification.
  • This error also occurs on Python 3.5 after upgrading to yosemite
  • This explains the situation.
  • “How can I make it bypass the verification?” is the wrong question. You should probably ask how to validate the certificate provided by the domain.

The Answer 1

324 people think this answer is useful

If you just want to bypass verification, you can create a new SSLContext. By default newly created contexts use CERT_NONE.

Be careful with this as stated in section

When calling the SSLContext constructor directly, CERT_NONE is the default. Since it does not authenticate the other peer, it can be insecure, especially in client mode where most of time you would like to ensure the authenticity of the server you’re talking to. Therefore, when in client mode, it is highly recommended to use CERT_REQUIRED.

But if you just want it to work now for some other reason you can do the following, you’ll have to import ssl as well:

input = input.replace("!web ", "")      
url = "" + input
req = urllib2.Request(url, headers={ 'X-Mashape-Key': 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' })
gcontext = ssl.SSLContext()  # Only for gangstars
info = urllib2.urlopen(req, context=gcontext).read()
Message.Chat.SendMessage ("" + info)

This should get round your problem but you’re not really solving any of the issues, but you won’t see the [SSL: CERTIFICATE_VERIFY_FAILED] because you now aren’t verifying the cert!

To add to the above, if you want to know more about why you are seeing these issues you will want to have a look at PEP 476.

This PEP proposes to enable verification of X509 certificate signatures, as well as hostname verification for Python’s HTTP clients by default, subject to opt-out on a per-call basis. This change would be applied to Python 2.7, Python 3.4, and Python 3.5.

There is an advised opt out which isn’t dissimilar to my advice above:

import ssl

# This restores the same behavior as before.
context = ssl._create_unverified_context()
urllib.urlopen("https://no-valid-cert", context=context)

It also features a highly discouraged option via monkeypatching which you don’t often see in python:

import ssl

ssl._create_default_https_context = ssl._create_unverified_context

Which overrides the default function for context creation with the function to create an unverified context.

Please note with this as stated in the PEP:

This guidance is aimed primarily at system administrators that wish to adopt newer versions of Python that implement this PEP in legacy environments that do not yet support certificate verification on HTTPS connections. For example, an administrator may opt out by adding the monkeypatch above to in their Standard Operating Environment for Python. Applications and libraries SHOULD NOT be making this change process wide (except perhaps in response to a system administrator controlled configuration setting).

If you want to read a paper on why not validating certs is bad in software you can find it here!

The Answer 2

418 people think this answer is useful

This isn’t a solution to your specific problem, but I’m putting it here because this thread is the top Google result for “SSL: CERTIFICATE_VERIFY_FAILED”, and it lead me on a wild goose chase.

If you have installed Python 3.6 on OSX and are getting the “SSL: CERTIFICATE_VERIFY_FAILED” error when trying to connect to an https:// site, it’s probably because Python 3.6 on OSX has no certificates at all, and can’t validate any SSL connections. This is a change for 3.6 on OSX, and requires a post-install step, which installs the certifi package of certificates. This is documented in the ReadMe, which you should find at /Applications/Python\ 3.6/ReadMe.rtf

The ReadMe will have you run this post-install script, which just installs certifi: /Applications/Python\ 3.6/Install\ Certificates.command

Release notes have some more info:

The Answer 3

76 people think this answer is useful

To expand on Craig Glennie’s answer:

in Python 3.6.1 on MacOs Sierra

Entering this in the bash terminal solved the problem:

pip install certifi
/Applications/Python\ 3.6/Install\ Certificates.command

The Answer 4

49 people think this answer is useful

On Windows, Python does not look at the system certificate, it uses its own located at ?\lib\site-packages\certifi\cacert.pem.

The solution to your problem:

  1. download the domain validation certificate as *.crt or *pem file
  2. open the file in editor and copy it’s content to clipboard
  3. find your cacert.pem location: from requests.utils import DEFAULT_CA_BUNDLE_PATH; print(DEFAULT_CA_BUNDLE_PATH)
  4. edit the cacert.pem file and paste your domain validation certificate at the end of the file.
  5. Save the file and enjoy requests!

The Answer 5

44 people think this answer is useful

My solution for Mac OS X:

1) Upgrade to Python 3.6.5 using the native app Python installer downloaded from the official Python language website

I’ve found that this installer is taking care of updating the links and symlinks for the new Python a lot better than homebrew.

2) Install a new certificate using “./Install Certificates.command” which is in the refreshed Python 3.6 directory

> cd "/Applications/Python 3.6/"
> sudo "./Install Certificates.command"

The Answer 6

38 people think this answer is useful

I was having a similar problem, though I was using urllib.request.urlopen in Python 3.4, 3.5, and 3.6. (This is a portion of the Python 3 equivalent of urllib2, per the note at the head of Python 2’s urllib2 documentation page.)

My solution was to pip install certifi to install certifi, which has:

… a carefully curated collection of Root Certificates for validating the trustworthiness of SSL certificates while verifying the identity of TLS hosts.

Then, in my code where I previously just had:

import urllib.request as urlrq

resp = urlrq.urlopen('')

I revised it to:

import urllib.request as urlrq
import certifi

resp = urlrq.urlopen('', cafile=certifi.where())

If I read the urllib2.urlopen documentation correctly, it also has a cafile argument. So, urllib2.urlopen([...], certifi.where()) might work for Python 2.7 as well.

UPDATE (2020-01-01): As of Python 3.6, the cafile argument to urlopen has been deprecated, with the context argument supposed to be specified instead. I found the following to work equally well on 3.5 through 3.8:

import urllib.request as urlrq
import certifi
import ssl

resp = urlrq.urlopen('', context=ssl.create_default_context(cafile=certifi.where()))

The Answer 7

33 people think this answer is useful

You could try adding this to your environment variables:


Note that this will disable all HTTP verification so is a bit of a sledgehammer approach, however if verification isn’t required it may be an effective solution.

The Answer 8

13 people think this answer is useful
import requests

import ssl

    _create_unverified_https_context = ssl._create_unverified_context
except AttributeError:
    # Legacy Python that doesn't verify HTTPS certificates by default
    # Handle target environment that doesn't support HTTPS verification
    ssl._create_default_https_context = _create_unverified_https_context

Taken from here

The Answer 9

9 people think this answer is useful

Like I’ve written in a comment, this problem is probably related to this SO answer.

In short: there are multiple ways to verify the certificate. The verification used by OpenSSL is incompatible with the trusted root certificates you have on your system. OpenSSL is used by Python.

You could try to get the missing certificate for Verisign Class 3 Public Primary Certification Authority and then use the cafile option according to the Python documentation:

urllib2.urlopen(req, cafile="verisign.pem")

The Answer 10

9 people think this answer is useful

I had a similar problem on one of my Linux machines. Generating fresh certificates and exporting an environment variable pointing to the certificates directory fixed it for me:

$ sudo update-ca-certificates --fresh
$ export SSL_CERT_DIR=/etc/ssl/certs

The Answer 11

7 people think this answer is useful

I need to add another answer because just like Craig Glennie, I went on a wild goose chase due to the many posts referring to this problem across the Web.

I am using MacPorts, and what I originally thought was a Python problem was in fact a MacPorts problem: it does not install a root certificate with its installation of openssl. The solution is to port install curl-ca-bundle, as mentioned in this blog post.

The Answer 12

6 people think this answer is useful

Solution for Anaconda

My setup is Anaconda Python 3.7 on MacOS with a proxy. The paths are different.

  • This is how you get the correct certificates path:
import ssl

which on my system produced

Out[35]: DefaultVerifyPaths(cafile='/miniconda3/ssl/cert.pem', capath=None,
 openssl_cafile_env='SSL_CERT_FILE', openssl_cafile='/miniconda3/ssl/cert.pem',
 openssl_capath_env='SSL_CERT_DIR', openssl_capath='/miniconda3/ssl/certs')

Once you know where the certificate goes, then you concatenate the certificate used by the proxy to the end of that file.

I had already set up conda to work with my proxy, by running:

conda config --set ssl_verify <pathToYourFile>.crt

If you don’t remember where your cert is, you can find it in ~/.condarc:

ssl_verify: <pathToYourFile>.crt

Now concatenate that file to the end of /miniconda3/ssl/cert.pem and requests should work, and in particular sklearn.datasets and similar tools should work.

Further Caveats

The other solutions did not work because the Anaconda setup is slightly different:

  • The path Applications/Python\ 3.X simply doesn’t exist.

  • The path provided by the commands below is the WRONG path

from requests.utils import DEFAULT_CA_BUNDLE_PATH

The Answer 13

6 people think this answer is useful
$ cd $HOME
$ wget --quiet
$ export SSL_CERT_FILE=$HOME/cacert.pem


The Answer 14

4 people think this answer is useful

Python 2.7.12 (default, Jul 29 2016, 15:26:22) fixed the mentioned issue. This information might help someone else.

The Answer 15

4 people think this answer is useful

For Python 3.4+ on Centos 6/7,Fedora, just install the trusted CA this way :

  1. Copy the CA.crt to /etc/pki/ca-trust/source/anchors/
  2. update-ca-trust force-enable
  3. update-ca-trust extract

The Answer 16

4 people think this answer is useful

I am surprised all these instruction didn’t solved my problem. Nonetheless, the diagnostic is correct (BTW, I am using Mac and Python3.6.1). So, to summarize the correct part :

  • On Mac, Apple is dropping OpenSSL
  • Python now uses it own set of CA Root Certificate
  • Binary Python installation provided a script to install the CA Root certificate Python needs (“/Applications/Python 3.6/Install Certificates.command”)
  • Read “/Applications/Python 3.6/ReadMe.rtf” for details

For me, the script doesn’t work, and all those certifi and openssl installation failed to fix too. Maybe because I have multiple python 2 and 3 installations, as well as many virtualenv. At the end, I need to fix it by hand.

pip install certifi   # for your virtualenv
mkdir -p /Library/Frameworks/Python.framework/Versions/3.6/etc/openssl
cp -a <your virtualenv>/site-package/certifi/cacert.pem \

If that still fails you. Then re/install OpenSSL as well.

port install openssl

The Answer 17

4 people think this answer is useful

I have found this over here

I found this solution, insert this code at the beginning of your source file:

import ssl

   _create_unverified_https_context = ssl._create_unverified_context
except AttributeError:
    # Legacy Python that doesn't verify HTTPS certificates by default
    # Handle target environment that doesn't support HTTPS verification
    ssl._create_default_https_context = _create_unverified_https_context

This code makes the verification undone so that the ssl certification is not verified.

The Answer 18

3 people think this answer is useful

I hang my head in semi-shame, as I had the same issue, except that in my case, the URL I was hitting was valid, the certificate was valid. What wasn’t valid was my connection out to the web. I had failed to add proxy details into the browser (IE in this case). This stopped the verification process from happening correctly.
Added in the proxy details and my python was then very happy .

The Answer 19

2 people think this answer is useful

Like you, I am using python 2.7 on my old iMac (OS X 10.6.8), I met the problem too, using urllib2.urlopen :


My programs were running fine without SSL certificate problems and suddently (after dowloading programs), they crashed with this SSL error.

The problem was the version of python used :

  1. No problem with and python-2.7.9-macosx10.6.pkg

  2. problem with the one instaled by Homebrew tool : “brew install python”, version located in /usr/local/bin.

A chapter, called Certificate verification and OpenSSL [CHANGED for Python 2.7.9], in /Applications/Python 2.7/ReadMe.rtf explains the problem with many details.

So, check, download and put in your PATH the right version of python.

The Answer 20

2 people think this answer is useful

Python 2.7 on Amazon EC2 with centOS 7

I had to set the env variable SSL_CERT_DIR to point to my ca-bundle which was located at /etc/ssl/certs/ca-bundle.crt

The Answer 21

2 people think this answer is useful

The SSL: CERTIFICATE_VERIFY_FAILED error could also occur because an Intermediate Certificate is missing in the ca-certificates package on Linux. For example, in my case the intermediate certificate “DigiCert SHA2 Secure Server CA” was missing in the ca-certificates package even though the Firefox browser includes it. You can find out which certificate is missing by directly running the wget command on the URL causing this error. Then you can search for the corresponding link to the CRT file for this certificate from the official website (e.g. in my case) of the Certificate Authority. Now, to include the certificate that is missing in your case, you may run the below commands using your CRT file download link instead:


mv DigiCertSHA2SecureServerCA.crt DigiCertSHA2SecureServerCA.der

openssl x509 -inform DER -outform PEM -in DigiCertSHA2SecureServerCA.der -out DigicertSHA2SecureServerCA.pem.crt

sudo mkdir /usr/share/ca-certificates/extra

sudo cp DigicertSHA2SecureServerCA.pem.crt /usr/share/ca-certificates/extra/

sudo dpkg-reconfigure ca-certificates

After this you may test again with wget for your URL as well as by using the python urllib package. For more details, refer to:

The Answer 22

1 people think this answer is useful


pip install –trusted-host packagename

It worked for me.

The Answer 23

1 people think this answer is useful

Take a look at

/Applications/Python 3.6/Install Certificates.command

You can also go to Aplications ans click on Certificates.command

The Answer 24

1 people think this answer is useful

In my case I was getting this error because requests and urllib3 versions were incompatible, giving the following error during installation:

ERROR: requests 2.21.0 has requirement urllib3<1.25,>=1.21.1, but you'll have urllib3 1.25 which is incompatible.

pip install 'urllib3<1.25' --force-reinstall

did the trick.

The Answer 25

1 people think this answer is useful

Another Anaconda solution. I was getting CERTIFICATE_VERIFY_FAILED in my Python 2.7 environment on macOS. It turns out the conda paths were bad:

base (3.7) environment:

>>> import ssl
>>> ssl.get_default_verify_paths()
DefaultVerifyPaths(cafile='/usr/local/anaconda3/ssl/cert.pem', capath=None, openssl_cafile_env='SSL_CERT_FILE', openssl_cafile='/usr/local/anaconda3/ssl/cert.pem', openssl_capath_env='SSL_CERT_DIR', openssl_capath='/usr/local/anaconda3/ssl/certs')

2.7 environment (paths did not exist!):

DefaultVerifyPaths(cafile='', capath=None, openssl_cafile_env='SSL_CERT_FILE', openssl_cafile='/usr/local/anaconda3/envs/py27/ssl/cert.pem', openssl_capath_env='SSL_CERT_DIR', openssl_capath='/usr/local/anaconda3/envs/py27/ssl/certs')

The fix:

cd /usr/local/anaconda3/envs/py27/
mkdir ssl
cd ssl
ln -s ../../../ssl/cert.pem

The Answer 26

1 people think this answer is useful

There are cases when you can not use insecure connections or pass ssl context into urllib request. Here my solution based on

In a case if you want use your own cert file

import ssl

def new_ssl_context_decorator(*args, **kwargs):
    kwargs['cafile'] = '/etc/ssl/certs/ca-certificates.crt'
    return ssl.create_default_context(*args, **kwargs)

ssl._create_default_https_context = ssl._create_unverified_context

or you can use shared file from certifi

def new_ssl_context_decorator(*args, **kwargs):
    import certifi
    kwargs['cafile'] = certifi.where()
    return ssl.create_default_context(*args, **kwargs)

The Answer 27

0 people think this answer is useful

If your on vCenter 6, you should instead add your vCenter’s vmware certificate authority cert to your OS’s list of trusted CA’s. To download your cert do the following

  1. Open your Web browser.
  2. Navigate to https://
  3. In the lower right-hand corner, click the Download Trusted Root CA link

On Fedora

  1. unzip and change the extension from .0 to .cer
  2. Copy it to the /etc/pki/ca-trust/source/anchors/
  3. run the update-ca-trust command.



The Answer 28

0 people think this answer is useful

installing steps for nltk (I had python3 (3.6.2) installed already in MAC OS X

sudo easy_install pip

use ignore installed option to ignore uninstalling previous version of six, else, it gives an error while uninstalling and does not movie forward

sudo pip3 install -U nltk --ignore-installed six

Check the installation of pip and python, use the ‘3’ versions

which python python2 python3
which pip pip2 pip3

Check if NLTK is installed

import nltk

Install SSL certificate prior to installing the examples book, else we will certificate error while installing the examples

/Applications/Python\ 3.6/Install\ Certificates.command
python3 -m nltk.downloader book

That completed the installation successfully of nltk and nltk_ata for book examples

The Answer 29

0 people think this answer is useful

Installing PyOpenSSL using pip worked for me (without converting to PEM):

pip install PyOpenSSL

The Answer 30

0 people think this answer is useful

I had this problem solved by closing Fiddler (an HTTP debugging proxy) check if you have a proxy enabled and try again.

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