urllib3 Uncaught exception from pyOpenSSL's shutdown call

The Fix

pip install urllib3==1.25

Based on closed urllib3/urllib3 issue #612 · PR/commit linked

Open PR/Commit

@@ -208,9 +208,13 @@ def sendall(self, data):
             data = data[sent:]
 
+    def shutdown(self):
+        # FIXME rethrow compatible exceptions should we ever use this
+        self.connection.shutdown()

fix.md

Option A — Upgrade to fixed release\npip install urllib3==1.25\nWhen NOT to use: Do not apply this fix if using a version of pyOpenSSL that does not support the shutdown method.\n\n

Why This Fix Works in Production

Trigger: Uncaught exception from pyOpenSSL's shutdown call
Mechanism: An uncaught exception occurs during pyOpenSSL's shutdown call
Why the fix works: Addresses an uncaught exception from pyOpenSSL's shutdown call by modifying the shutdown and close methods. (first fixed release: 1.25).

Why This Breaks in Prod

An uncaught exception occurs during pyOpenSSL's shutdown call
Production symptom (often without a traceback): Uncaught exception from pyOpenSSL's shutdown call

Proof / Evidence

GitHub issue: #612
Fix PR: https://github.com/urllib3/urllib3/pull/614
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: 0.82

Discussion

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

Jump to Sources Open on GitHub

“See https://github.com/pypa/pip/issues/2753 for more details”

Issue thread · issue description · source

Failure Signature (Search String)

Uncaught exception from pyOpenSSL's shutdown call

Copy-friendly signature

signature.txt

Failure Signature
-----------------
Uncaught exception from pyOpenSSL's shutdown call

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
Uncaught exception from pyOpenSSL's shutdown call

What Broke

The application experiences unexpected crashes during SSL shutdown operations.

Why It Broke

An uncaught exception occurs during pyOpenSSL's shutdown call

Fix Options (Details)

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

pip install urllib3==1.25

When NOT to use: Do not apply this fix if using a version of pyOpenSSL that does not support the shutdown method.

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/614

First fixed release: 1.25

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

When NOT to Use This Fix

Do not apply this fix if using a version of pyOpenSSL that does not support the shutdown method.

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:ssl-handshake urllib3 hub urllib3 best practices All hubs All clusters

Related clusters: Configuration error Data consistency Other

Sources

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

urllib3 Uncaught exception from pyOpenSSL's shutdown call (Fix)