HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.
History

Thu, 03 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Pydantic
Pydantic httpx2
Vendors & Products Pydantic
Pydantic httpx2

Thu, 03 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 03 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Wed, 02 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.
Title HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)
Weaknesses CWE-409
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-02T18:03:05.010Z

Updated: 2026-09-03T14:31:19.366Z

Reserved: 2026-09-01T16:27:58.130Z

Link: CVE-2026-84382

cve-icon Vulnrichment

Updated: 2026-09-03T14:09:08.128Z

cve-icon NVD

Status : Received

Published: 2026-09-02T19:18:08.353

Modified: 2026-09-03T15:17:35.513

Link: CVE-2026-84382

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-02T18:03:05Z

Links: CVE-2026-84382 - Bugzilla