AIOHTTP's C parser (llhttp) accepts null bytes and control characters in response header values - header injection/security bypass

Summary The C parser the default for most installs accepted null bytes and control characters in request headers. Impact An attacker could send header values that are interpreted differently than expected due to the presence of control characters. For example, request.url.origin may return a...

AIOHTTP has HTTP response splitting via \r in reason phrase

Summary An attacker who controls the reason parameter when creating a Response may be able to inject extra headers or similar exploits. Impact In the unlikely situation that an application allows untrusted data to be used in the response's reason parameter, then an attacker could manipulate the...

HTTP Response Splitting

Overview Affected versions of this package are vulnerable to HTTP Response Splitting via the reason parameter in the HTTP response creation process. An attacker can inject unauthorized headers or manipulate the HTTP response by supplying specially crafted input containing carriage return...

EUVD-2026-18044

AIOHTTP has HTTP response splitting via \r in reason phrase...

GHSA-MWH4-6H8G-PG8W AIOHTTP has HTTP response splitting via \r in reason phrase

Summary An attacker who controls the reason parameter when creating a Response may be able to inject extra headers or similar exploits. Impact In the unlikely situation that an application allows untrusted data to be used in the response's reason parameter, then an attacker could manipulate the...

EUVD-2026-18042

AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect...

Information Exposure

Overview Affected versions of this package are vulnerable to Information Exposure in the handling of cross-origin redirects, where Cookie and Proxy-Authorization headers are not properly removed. An attacker can obtain sensitive information by causing a user to follow a redirect to a malicious...

GHSA-966J-VMVW-G2G9 AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect

Summary When following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. Impact The Cookie and Proxy-Authorizations headers could contain sensitive information which may be leaked to an unintended party after following...

AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect

Summary When following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. Impact The Cookie and Proxy-Authorizations headers could contain sensitive information which may be leaked to an unintended party after following...

GHSA-M5QP-6W8W-W647 AIOHTTP has a Multipart Header Size Bypass

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...

AIOHTTP has a Multipart Header Size Bypass

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...

GHSA-2VRM-GR82-F7M5 AIOHTTP has CRLF injection through multipart part content type header construction

Summary An attacker who controls the contenttype parameter in aiohttp could use this to inject extra headers or similar exploits. Impact If an application allows untrusted data to be used for the multipart contenttype parameter when constructing a request, an attacker may be able to manipulate th...

EUVD-2026-18037

AIOHTTP has CRLF injection through multipart part content type header construction...

AIOHTTP has CRLF injection through multipart part content type header construction

Summary An attacker who controls the contenttype parameter in aiohttp could use this to inject extra headers or similar exploits. Impact If an application allows untrusted data to be used for the multipart contenttype parameter when constructing a request, an attacker may be able to manipulate th...

AZL-81773 CVE-2026-34518 affecting package python-aiohttp 3.6.2-3

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. This issue has been patched in version 3.13.4...

DEBIAN-CVE-2026-34519

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the reason parameter when creating a Response may be able to inject extra headers or similar exploits. This issue has been patched in version 3.13.4...

CVE-2026-34518

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. This issue has been patched in version 3.13.4...

CVE-2026-34518

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. This issue has been patched in version 3.13.4...

UBUNTU-CVE-2026-34518

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. This issue has been patched in version 3.13.4...

AZL-81776 CVE-2026-34519 affecting package python-aiohttp 3.6.2-3

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the reason parameter when creating a Response may be able to inject extra headers or similar exploits. This issue has been patched in version 3.13.4...