CVE-2026-34517: CWE-770: Allocation of Resources Without Limits or Throttling in aio-libs aiohttp
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
AI Analysis
Technical Summary
CVE-2026-34517 is a resource allocation vulnerability in aiohttp, an asynchronous HTTP client/server framework for Python. The flaw involves reading entire multipart form fields into memory before checking the configured client_max_size limit, potentially allowing excessive memory consumption. This behavior occurs in versions before 3.13.4. The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). The issue has been addressed and patched in aiohttp version 3.13.4.
Potential Impact
The vulnerability can cause aiohttp servers to consume excessive memory when processing certain multipart form fields, potentially leading to resource exhaustion. The CVSS score is low (2.7), indicating limited impact and exploitability. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade aiohttp to version 3.13.4 or later, where this issue has been fixed. No additional mitigation is required once the patch is applied.
CVE-2026-34517: CWE-770: Allocation of Resources Without Limits or Throttling in aio-libs aiohttp
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
CVSS v4.0
Score 2.7low
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-34517 is a resource allocation vulnerability in aiohttp, an asynchronous HTTP client/server framework for Python. The flaw involves reading entire multipart form fields into memory before checking the configured client_max_size limit, potentially allowing excessive memory consumption. This behavior occurs in versions before 3.13.4. The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). The issue has been addressed and patched in aiohttp version 3.13.4.
Potential Impact
The vulnerability can cause aiohttp servers to consume excessive memory when processing certain multipart form fields, potentially leading to resource exhaustion. The CVSS score is low (2.7), indicating limited impact and exploitability. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade aiohttp to version 3.13.4 or later, where this issue has been fixed. No additional mitigation is required once the patch is applied.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-03-30T16:03:31.047Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 69cec35ae6bfc5ba1dfb4d05
Added to database: 04/02/2026, 19:28:26 UTC
Last enriched: 06/24/2026, 15:08:46 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 132
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