CVE-2026-84382
HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-409 |
| Vendor | pydantic |
| Product | httpx2 |
| Published | Sep 2, 2026 |
| Last Updated | Sep 3, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
pydantic / httpx2
< 2.12.0
References
github.com: https://github.com/pydantic/httpx2/security/advisories/GHSA-8xx6-hgc6-gc2m github.com: https://github.com/pydantic/httpx2/pull/1126 github.com: https://github.com/pydantic/httpx2/commit/4fd0c70a3f207c618b145934792f791bccfb39f8 github.com: https://github.com/pydantic/httpx2/releases/tag/v2.12.0