CVE-2026-34520 — AIOHTTP: C parser (llhttp) accepts null bytes and control characters in response header values - header injection / security bypass
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, the C parser (the default for most installs) accepted null bytes and con…
Published: 2026-04-01 · CVSS: 2.7 · CVSS 4.0
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, the C parser (the default for most installs) accepted null bytes and control characters in response headers. This issue has been patched in version 3.13.4.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7