CVE-2026-34516
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.
02 / AFFECTED SOFTWARE
Affected packages
304 explicit affected versions
304 explicit affected versions
151 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.
### Summary A response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. ### Impact Multipart headers were not subject to the same size restrictions in place for normal headers, potentially allowing substantially more data to be loaded into memory than intended. However, other restrictions in place limit the impact of this vulnerability. ----- Patch: https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.
05 / REFERENCES
Further evidence
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34516.json
- https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f
- https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-m5qp-6w8w-w647
- https://nvd.nist.gov/vuln/detail/CVE-2026-34516
- https://github.com/aio-libs/aiohttp