Aiohttp Aiohttp vulnerabilities

CVE-2026-54280 High · 7.5 CWE-404 Jun 22, 2026

AIOHTTP: Payload Response Resources Are Not Closed After Mid-Body Disconnect

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, payload resources are not closed correctly when a client disconnects in the middle of a write. If a payload is using an open file or similar limited resource, then an attacker may be able to cause resource starvation temporarily until garbage collection or similar closes the file. This vulnerability is fixed in 3.14.1.

CVE-2026-54279 High · 7.5 CWE-665 Jun 22, 2026

AIOHTTP: Host-Only Cookies Become Domain Cookies After CookieJar Persistence

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, host-only cookies that are saved with CookieJar.save() and then restored later with CookieJar.load() lose their host-only status. This vulnerability is fixed in 3.14.1.

CVE-2026-54278 High · 7.5 CWE-409 Jun 22, 2026

AIOHTTP: Unread Compressed Request Bodies Bypass client_max_size During Cleanup

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, during cleanup it is possible for a compressed request body to be decompressed into memory in one chunk. An attacker may be able to send a compressed payload in specific situations that could be decompressed into memory, potentially leading to DoS (a zip bomb edge case). This vulnerability is fixed in 3.14.1.

CVE-2026-54277 High · 7.5 CWE-770 Jun 22, 2026

AIOHTTP: C HTTP Parser Bypasses max_line_size for Fragmented Lines

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, it is possible to bypass the max_line_size check in parts of an HTTP request in the C parser. If using the optimised C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS. This vulnerability is fixed in 3.14.1.

CVE-2026-54276 Medium · 6.1 CWE-601 Jun 22, 2026

AIOHTTP: DigestAuthMiddleware Applies Credentials to Cross-Origin Redirect Challenges

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, DigestAuthMiddleware can send an authentication response after following a cross-origin redirect. This likely requires an open redirect vulnerability or similar on the target domain for an attacker to be able to execute. Further, the attacker is only receiving the digest, so should only be able to extract the user's credentials if the cryptography is weak or there is some kind of password reuse. This vulnerability is fixed in 3.14.1.

CVE-2026-54275 High · 7.5 CWE-297 Jun 22, 2026

AIOHTTP: TLS Server Hostname Override Is Ignored When Reusing HTTPS Connections

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, the server_hostname TLS SNI check can be bypassed when an existing connection is reused. If an application makes multiple requests to the same domain, but with different per-request server_hostname parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check. This vulnerability is fixed in 3.14.1.

CVE-2026-54274 High · 7.5 CWE-770 Jun 22, 2026

AIOHTTP: Incomplete websocket frame payloads bypass memory limits

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, if an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use. This vulnerability is fixed in 3.14.1.

CVE-2026-54273 High · 7.5 CWE-770 Jun 22, 2026

AIOHTTP: HTTP/1 Pipelined Requests Queue Without Limit

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, no limit was present on the number of pipelined requests that could be queued. An attacker may be able to use pipelined requests to use excessive amounts of memory, potentially leading to DoS. This vulnerability is fixed in 3.14.1.

CVE-2026-50269 High · 7.5 CWE-93 Jun 22, 2026

AIOHTTP: CRLF injection in multipart headers

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar. In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request. This vulnerability is fixed in 3.14.0.

CVE-2026-47265 High · 7.5 CWE-346 Jun 2, 2026

AIOHTTP vulnerable to cross-origin redirect with per-request cookies

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.14.0, cookies set with the `cookies` parameter on requests are sent after following a cross-origin redirect. If a developer uses the `cookies` parameter on a per-request basis then sensitive data might be leaked to an attacker if they manage to control a redirect. Version 3.14.0 patches the issue. If unable to upgrade, using a `Cookie` header in the `headers` parameter is not vulnerable.

CVE-2026-34993 High · 7.3 CWE-502 Jun 2, 2026

AIOHTTP Vulnerable to Deserialization of Untrusted Data

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.14.0, using ``CookieJar.load()`` with untrusted input may allow arbitrary code execution. Most applications using this function will be doing so with the user's own data, so this is unlikely to affect many applications. Version 3.14.0 patches the issue. If an application does allow attacker controlled files to be loaded, a workaround on older releases would be to sanitize the files before loading.

CVE-2026-34525 Medium · 5.3 CWE-20 Apr 1, 2026

AIOHTTP: Duplicate Host header accepted

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, multiple Host headers were allowed in aiohttp. This issue has been patched in version 3.13.4.

CVE-2026-34520 Critical · 9.1 CWE-113 Apr 1, 2026

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 control characters in response headers. This issue has been patched in version 3.13.4.

CVE-2026-34519 Medium · 5.3 CWE-113 Apr 1, 2026

AIOHTTP: HTTP response splitting via \r in reason phrase

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 Medium · 5.3 CWE-200 Apr 1, 2026

AIOHTTP: Cookie and Proxy-Authorization headers leaked on cross-origin redirect

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-2026-34517 Medium · 5.3 CWE-770 Apr 1, 2026

AIOHTTP: Late size enforcement for non-file multipart fields causes memory DoS

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.

CVE-2026-34516 High · 7.5 CWE-770 Apr 1, 2026

AIOHTTP: Multipart Header Size Bypass

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.

CVE-2026-34515 High · 7.5 CWE-36 Apr 1, 2026

AIOHTTP: UNC SSRF/NTLMv2 Credential Theft/Local File Read in static resource handler on Windows

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, on Windows the static resource handler may expose information about a NTLMv2 remote path. This issue has been patched in version 3.13.4.

CVE-2026-34514 Medium · 5.3 CWE-113 Apr 1, 2026

AIOHTTP: CRLF injection in multipart part content type header construction

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the content_type parameter in aiohttp could use this to inject extra headers or similar exploits. This issue has been patched in version 3.13.4.

CVE-2026-34513 High · 7.5 CWE-770 Apr 1, 2026

AIOHTTP: Denial of Service (DoS) via Unbounded DNS Cache in TCPConnector

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an unbounded DNS cache could result in excessive memory usage possibly resulting in a DoS situation. This issue has been patched in version 3.13.4.

CVE-2026-22815 High · 7.5 CWE-400 Apr 1, 2026

AIOHTTP: Uncapped memory usage possible through aiohttp allowing unlimited trailer headers

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, insufficient restrictions in header/trailer handling could cause uncapped memory usage. This issue has been patched in version 3.13.4.

CVE-2025-69230 Medium · 5.3 CWE-779 Jan 5, 2026

AIOHTTP Vulnerable to Cookie Parser Warning Storm

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. In versions 3.13.2 and below, reading multiple invalid cookies can lead to a logging storm. If the cookies attribute is accessed in an application, then an attacker may be able to trigger a storm of warning-level logs using a specially crafted Cookie header. This issue is fixed in 3.13.3.

CVE-2025-69229 Medium · 5.3 CWE-770 Jan 5, 2026

AIOHTTP vulnerable to DoS through chunked messages

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. In versions 3.13.2 and below, handling of chunked messages can result in excessive blocking CPU usage when receiving a large number of chunks. If an application makes use of the request.read() method in an endpoint, it may be possible for an attacker to cause the server to spend a moderate amount of blocking CPU time (e.g. 1 second) while processing the request. This could potentially lead to DoS as the server would be unable to handle other requests during that time. This issue is fixed in version 3.13.3.

CVE-2025-69228 High · 7.5 CWE-770 Jan 5, 2026

AIOHTTP vulnerable to denial of service through large payloads

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below allow a request to be crafted in such a way that an AIOHTTP server's memory fills up uncontrollably during processing. If an application includes a handler that uses the Request.post() method, an attacker may be able to freeze the server by exhausting the memory. This issue is fixed in version 3.13.3.

CVE-2025-69227 High · 7.5 CWE-835 Jan 5, 2026

AIOHTTP vulnerable to DoS when bypassing asserts

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below allow for an infinite loop to occur when assert statements are bypassed, resulting in a DoS attack when processing a POST body. If optimizations are enabled (-O or PYTHONOPTIMIZE=1), and the application includes a handler that uses the Request.post() method, then an attacker may be able to execute a DoS attack with a specially crafted message. This issue is fixed in version 3.13.3.