Requests IOError when making https requests from executable

The Fix

pip install requests==2.27.0

Based on closed psf/requests issue #4369 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Jump to Verify Open PR/Commit

@@ -179,3 +179,4 @@ Patches and Suggestions
 - Matt Liu <[email protected]> (`@mlcrazy <https://github.com/mlcrazy>`_)
 - Taylor Hoff <[email protected]> (`@PrimordialHelios <https://github.com/PrimordialHelios>`_)
+- Arthur Vigil (`@ahvigil <https://github.com/ahvigil>`_)
diff --git a/HISTORY.rst b/HISTORY.rst
index 89a0b0dc16..e6281c1e77 100644

repro.py

# will generate a barebones zip archive from the contents of this folder
mkdir zipapptest

# produce a 2 line __main__.py that reproduces the bug
cat >zipapptest/__main__.py <<EOF
import requests
requests.get('https://www.google.com')
EOF

# I will try to include the requests dependency in the archive
pip install -t zipapptest requests

# generate an executable zip from the above folder
python -m zipapp --python $(which python) zipapptest

# try to run the generated archive
./zipapptest.pyz

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\npip install requests==2.27.0\nWhen NOT to use: Do not use this fix if the application does not run from a zip archive.\n\n

Why This Fix Works in Production

Trigger: "__main__", mod_spec)
Mechanism: The requests library fails to load CA certs from a zip archive due to incorrect path handling
Why the fix works: Resolves the issue by checking whether the default CA certificate bundle is being imported from a zip archive and extracts it to a temporary folder if necessary. (first fixed release: 2.27.0).

Production impact:

If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

Shows up under Python 3.6 in real deployments (not just unit tests).
The requests library fails to load CA certs from a zip archive due to incorrect path handling
Surfaces as: Traceback (most recent call last):

Proof / Evidence

GitHub issue: #4369
Fix PR: https://github.com/psf/requests/pull/4371
First fixed release: 2.27.0
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.42

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“Python has supported running packaged zip files since 2.6. The zipapp module newly introduced in python 3 is supposed to make it even easier to create executable python zip archives. As part of this, the contents of the zip archive are adde”

Issue thread · issue description · source

Failure Signature (Search String)

"__main__", mod_spec)

Error Message

Stack trace

error.txt

Error Message
-------------
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/local/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "./zipapptest.pyz/__main__.py", line 2, in <module>
  File "./zipapptest.pyz/requests/api.py", line 72, in get
  File "./zipapptest.pyz/requests/api.py", line 58, in request
  File "./zipapptest.pyz/requests/sessions.py", line 508, in request
  File "./zipapptest.pyz/requests/sessions.py", line 618, in send
  File "./zipapptest.pyz/requests/adapters.py", line 407, in send
  File "./zipapptest.pyz/requests/adapters.py", line 226, in cert_verify
OSError: Could not find a suitable TLS CA certificate bundle, invalid path: ./zipapptest.pyz/certifi/cacert.pem

Minimal Reproduction

repro.py

# will generate a barebones zip archive from the contents of this folder
mkdir zipapptest

# produce a 2 line __main__.py that reproduces the bug
cat >zipapptest/__main__.py <<EOF
import requests
requests.get('https://www.google.com')
EOF

# I will try to include the requests dependency in the archive
pip install -t zipapptest requests

# generate an executable zip from the above folder
python -m zipapp --python $(which python) zipapptest

# try to run the generated archive
./zipapptest.pyz

Environment

Python: 3.6

What Broke

HTTPS requests fail with IOError when requests is run from a zip archive.

Why It Broke

The requests library fails to load CA certs from a zip archive due to incorrect path handling

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install requests==2.27.0

When NOT to use: Do not use this fix if the application does not run from a zip archive.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/psf/requests/pull/4371

First fixed release: 2.27.0

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

Do not use this fix if the application does not run from a zip archive.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Add a TLS smoke test that performs a real handshake in CI (include CA bundle validation and hostname checks).
Alert on handshake failures by error string and endpoint to catch cert/CA changes quickly.

Version Compatibility Table

Version	Status
2.27.0	Fixed

Related Issues

No related fixes found.

Cluster: requests:configuration-error Requests hub Requests best practices All hubs All clusters

Related clusters: Data consistency SSL handshake Other

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.

Requests IOError when making https requests from executable zip archive (Fix)