urllib3 setup.py extra_require for certifi, pyopenssl,

The Fix

pip install urllib3==1.25

Based on closed urllib3/urllib3 issue #677 · 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%.

Open PR/Commit

@@ -142,6 +142,32 @@ Now you can continue using urllib3 as you normally would.
 For more details, check the :mod:`~urllib3.contrib.pyopenssl` module.
 
+Installing urllib3 with SNI support and certificates
+----------------------------------------------------
+

fix.md

Option A — Upgrade to fixed release\npip install urllib3==1.25\nWhen NOT to use: This fix is not suitable for users who do not require SNI support.\n\n

Why This Fix Works in Production

Trigger: setup.py extra_require for certifi, pyopenssl, other?
Mechanism: Added a 'secure' extras point to setup.py for easier installation of recommended dependencies.
Why the fix works: Added a 'secure' extras point to setup.py for easier installation of recommended dependencies. (first fixed release: 1.25).

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

Production symptom (often without a traceback): setup.py extra_require for certifi, pyopenssl, other?

Proof / Evidence

GitHub issue: #677
Fix PR: https://github.com/urllib3/urllib3/pull/678
First fixed release: 1.25
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.65

Discussion

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

Jump to Sources Open on GitHub

“Someday would be nice to make that the default, and maybe have a urllib3[minimal] but that's tricky since pyopenssl requires several system packages (build-essential, libffi-dev,…”

@shazow · 2015-07-17 · repro detail · source

“On Windows or Lubuntu we will have to compile cffi and crytography if we want to use pyOpenSSL, I wonder if pyOpenSSL can work without…”

@anatasiajp · 2015-07-26 · source

“@cattleyavns pyOpenSSL cannot work without cryptography which in turn cannot work without cffi.”

@sigmavirus24 · 2015-07-26 · source

“However, cryptography ships windows wheels that require no compilation on that platform.”

@Lukasa · 2015-07-26 · source

Failure Signature (Search String)

setup.py extra_require for certifi, pyopenssl, other?
Someday would be nice to make that the default, and maybe have a `urllib3[minimal]` but that's tricky since pyopenssl requires several system packages (build-essential,

Copy-friendly signature

signature.txt

Failure Signature
-----------------
setup.py extra_require for certifi, pyopenssl, other?
Someday would be nice to make that the default, and maybe have a `urllib3[minimal]` but that's tricky since pyopenssl requires several system packages (build-essential, libffi-dev, and libssl-dev).

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
setup.py extra_require for certifi, pyopenssl, other?
Someday would be nice to make that the default, and maybe have a `urllib3[minimal]` but that's tricky since pyopenssl requires several system packages (build-essential, libffi-dev, and libssl-dev).

What Broke

Users had difficulty installing recommended security dependencies for urllib3.

Fix Options (Details)

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

pip install urllib3==1.25

When NOT to use: This fix is not suitable for users who do not require SNI support.

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

Fix reference: https://github.com/urllib3/urllib3/pull/678

First fixed release: 1.25

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

When NOT to Use This Fix

This fix is not suitable for users who do not require SNI support.

Did This Fix Work in Your Case?

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

Prevention

Add a CI check that diffs key outputs after upgrades (OpenAPI schema snapshots, JSON payload shapes, CLI output).
Upgrade behind a canary and run integration tests against the canary before 100% rollout.
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
1.25	Fixed

Related Issues

No related fixes found.

Cluster: urllib3:configuration-error urllib3 hub urllib3 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.

urllib3 setup.py extra_require for certifi, pyopenssl, other? (Fix)