urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory — GHSA-VXQ7-64XX-V4GW

Summary

## Impact urllib3's [streaming API](https://urllib3.readthedocs.io/en/2.7.0/advanced-usage.html#streaming-and-i-o) is designed for efficiently handling large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When decoding a [chunked-transfer-encoded response](https://httpwg.org/specs/rfc9112.html#chunked.encoding), this API reads each chunk's size…

Timeline

Published by source

2026-09-30

Risk context

• Reported severity or threat level: high.
• Reported CVSS score: 8.9 out of 10.
• Review exposure for the affected product or family: pip: urllib3.

Product

pip: urllib3

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-VXQ7-64XX-V4GW

Source

GitHub

Vendor

GitHub

Published by source

2026-09-30

Last source activity

2026-09-30

Additional identifiers

CVE-2026-97689

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.