Vulnerability · Published Sep 2, 2026 · Assigned by GitHub_M
CVE-2026-84382HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)
High 7.5
In plain English
A high-severity security flaw in httpx2 from pydantic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | python-httpx2 | 2.12.0-1 | DEBIAN-CVE-2026-84382 |
| PyPI | httpx2 | 2.12.0 | GHSA-8xx6-hgc6-gc2m |
| PyPI | httpx2 | 2.12.0 | PYSEC-2026-3846 |
| Ubuntu:26.10 | python-httpx2 | no fix listed | UBUNTU-CVE-2026-84382 |
Affected products (as reported)
Weakness: CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/pydantic/httpx2/security/advisories/GHSA-8xx6-hgc6-gc2m x_refsource_CONFIRM
- https://github.com/pydantic/httpx2/pull/1126 x_refsource_MISC
- https://github.com/pydantic/httpx2/commit/4fd0c70a3f207c618b145934792f791bccfb39f8 x_refsource_MISC
- https://github.com/pydantic/httpx2/releases/tag/v2.12.0 x_refsource_MISC