The Fix
pip install urllib3==1.26.9
Based on closed urllib3/urllib3 issue #2566 · PR/commit linked
@@ -0,0 +1 @@
@@ -0,0 +1 @@
+``urllib3.contrib.pyopenssl`` module no longer supports using SSLv3.0 even when support is available from the compiled OpenSSL library.
Option A — Upgrade to fixed release\npip install urllib3==1.26.9\nWhen NOT to use: This fix should not be applied if SSLv3 support is required for legacy systems.\n\n
Why This Fix Works in Production
- Trigger: Create changelog entry for pyOpenSSL dropping SSLv3
- Mechanism: Adds a changelog entry indicating that the `urllib3.contrib.pyopenssl` module no longer supports SSLv3.
- Why the fix works: Adds a changelog entry indicating that the `urllib3.contrib.pyopenssl` module no longer supports SSLv3. (first fixed release: 1.26.9).
Why This Breaks in Prod
- Production symptom (often without a traceback): Create changelog entry for pyOpenSSL dropping SSLv3
Proof / Evidence
- GitHub issue: #2566
- Fix PR: https://github.com/urllib3/urllib3/pull/2573
- First fixed release: 1.26.9
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.95
- 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).
“#2233”
Failure Signature (Search String)
- Create changelog entry for pyOpenSSL dropping SSLv3
Copy-friendly signature
Failure Signature
-----------------
Create changelog entry for pyOpenSSL dropping SSLv3
Error Message
Signature-only (no traceback captured)
Error Message
-------------
Create changelog entry for pyOpenSSL dropping SSLv3
What Broke
Potential security vulnerabilities due to continued support for SSLv3 in production environments.
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install urllib3==1.26.9
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/2573
First fixed release: 1.26.9
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix should not be applied if SSLv3 support is required for legacy systems.
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 |
|---|---|
| 1.26.9 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.