urllib3 Calling .read() on a request returns an empty

The Fix

pip install urllib3==1.26.13

Based on closed urllib3/urllib3 issue #715 · 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

@@ -66,11 +66,11 @@ jobs:
             experimental: false
             nox-session: test-3.9
-          - python-version: 3.11-dev
+          - python-version: 3.11
             os: ubuntu-20.04

fix.md

Option A — Upgrade to fixed release\npip install urllib3==1.26.13\nWhen NOT to use: This fix should not be used if the application relies on the previous behavior of read() returning empty strings.\n\n

Why This Fix Works in Production

Trigger: http = urllib3.PoolManager(timeout=65)
Mechanism: Standardizes the behavior of HTTPResponse.read() to prevent returning empty strings when content is available.
Why the fix works: Standardizes the behavior of HTTPResponse.read() to prevent returning empty strings when content is available. (first fixed release: 1.26.13).

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): http = urllib3.PoolManager(timeout=65)

Proof / Evidence

GitHub issue: #715
Fix PR: https://github.com/urllib3/urllib3/pull/2798
First fixed release: 1.26.13
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.95
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.81

Discussion

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

Jump to Sources Open on GitHub

“I believe this was fixed in https://github.com/urllib3/urllib3/pull/2798 and will be available in v2.0.0 (which is pre-released right now!)”

@sethmlarson · 2023-01-02 · confirmation · source

“Thanks for this! However, if you looked a little more closely at the issues list you might have seen that the second one down is…”

@Lukasa · 2015-10-09 · source

“This is about documentation. You cannot use read() by default, because by default all the content is consumed into data. If you want read() to…”

@Lukasa · 2015-10-09 · source

“Yeaaaaaa, this is sucky. I'm sorry. :( I consider this issue an extension (or dupe?) of https://github.com/shazow/urllib3/issues/436.”

@shazow · 2015-10-10 · source

Failure Signature (Search String)

http = urllib3.PoolManager(timeout=65)
>> # ... your internet connection fails momentarily ...

Copy-friendly signature

signature.txt

Failure Signature
-----------------
http = urllib3.PoolManager(timeout=65)
>> # ... your internet connection fails momentarily ...

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
http = urllib3.PoolManager(timeout=65)
>> # ... your internet connection fails momentarily ...

What Broke

Users experienced empty responses when calling read() on HTTPResponse, causing confusion and incorrect behavior.

Fix Options (Details)

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

pip install urllib3==1.26.13

When NOT to use: This fix should not be used if the application relies on the previous behavior of read() returning empty strings.

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/2798

First fixed release: 1.26.13

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

When NOT to Use This Fix

This fix should not be used if the application relies on the previous behavior of read() returning empty strings.

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.
Make timeouts explicit and test them (unit + integration) to avoid silent behavior changes.
Instrument retries (attempt count + reason) and alert on spikes to catch dependency slowdowns.

Version Compatibility Table

Version	Status
1.26.13	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 Calling .read() on a request returns an empty string (Fix)