pydantic httpx2 up to 2.11.x Content Decoders _decoders.py iter_bytes/aiter_bytes allocation of resources

Summaryinfo

A vulnerability identified as problematic has been detected in pydantic httpx2 up to 2.11.x. This issue affects the function iter_bytes/aiter_bytes of the file src/httpx2/httpx2/_decoders.py of the component Content Decoders. This manipulation causes allocation of resources. This vulnerability is handled as CVE-2026-84382. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in pydantic httpx2 up to 2.11.x and classified as problematic. Affected by this vulnerability is the function iter_bytes/aiter_bytes of the file src/httpx2/httpx2/_decoders.py of the component Content Decoders. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-84382 since 09/01/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 2.12.0 eliminates this vulnerability.

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Productinfo

Vendor

• pydantic

Name

• httpx2

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11

Website

• Product: https://github.com/pydantic/httpx2/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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