CVE-2026-84382HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)
Updated under an hour ago ()
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It affects pydantic httpx2. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-409
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 3, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
pydantic httpx2 pydantic:httpx2 (from the name) | before 2.12.0 | CNA record |
References
- https://github.com/pydantic/httpx2/security/advisories/GHSA-8xx6-hgc6-gc2mx-refsource-confirm
- https://github.com/pydantic/httpx2/pull/1126x-refsource-misc
- https://github.com/pydantic/httpx2/commit/4fd0c70a3f207c618b145934792f791bccfb39f8x-refsource-misc
- https://github.com/pydantic/httpx2/releases/tag/v2.12.0x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.