CVE WatchNov 13, 2026

CVE-2026-128132

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the WebSocket reader continues parsing fram

CVSS

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No CVSS

EPSS

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KEV

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Exploit Today

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0-100

Published: Nov 13, 2026 · Last modified: Nov 13, 2026 · CWE-400 · CWE-770

EPSS · 30d

Not enough EPSS history yet.

Technical description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the WebSocket reader continues parsing frames already received after the receive queue pauses the transport, and empty messages are not counted toward the queue size. With permessage-deflate, one read of compressed frames can add many megabytes of decompressed messages to the receive queue. A remote peer can send many small or compressed messages faster than the application consumes them and cause excessive memory use in a server or client. This issue is fixed in version 3.14.4.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-128131—

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———AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, aiohttp decompresses each member of a payload containing many concatenated gzip, deflate, or zstd streams by passing the entire remaining input to a new decompressor, causing quadratic CPU use. Empty members produce no output, so client_max_size and output backpressure do not limit the work. A remote attacker can block a server event loop with a crafted compressed request body or WebSocket message, and a malicious server can similarly block a client. This issue is fixed in version 3.14.4.4h CVE-2026-128130—

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———AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, when the pipelined request queue is full, the pure-Python parser stores the unparsed remainder internally and also returns the same data to its caller. After a handler declines an upgrade request, the caller feeds the remainder back to the parser, causing the buffer to grow with each handled request and dispatching already-handled requests to the application again. The issue affects deployments using AIOHTTP_NO_EXTENSIONS or otherwise running without the standard C-extension wheel, and can cause excessive memory use and repeated request processing. This issue is fixed in version 3.14.4.4h CVE-2026-128129—

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———AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, aiohttp buffers all additional connection data received while a request marked for upgrade, such as a WebSocket handshake, is being handled, without a size limit or flow control. A remote attacker can stream data behind an upgrade request to a handler that does not immediately accept or reject the upgrade and cause unbounded memory consumption. This issue is fixed in version 3.14.4.3h CVE-2026-1281287.5 HIG

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———AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the C WebSocket reader adds a declared frame length to the size of an already buffered partial message using signed 64-bit arithmetic. A length near two to the power of 63 can overflow, allowing the max_msg_size check to pass. A remote peer can send a small non-final fragment followed by an oversized message and cause unbounded memory consumption. The Python WebSocket reader is unaffected. This issue is fixed in version 3.14.4.4h CVE-2026-128127—

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———AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, BodyPartReader.read_chunk() processing a multipart part with Content-Transfer-Encoding set to base64 keeps reading until the chunk length is a multiple of four without enforcing a byte limit. A short Content-Length or a long run of whitespace can cause one call to read the remaining body into memory before the size check or spin on the event loop. A remote attacker can send such a multipart request to a handler that reads multipart data and bypass client_max_size. This issue is fixed in version 3.14.4.4h CVE-2026-1280897.5 HIG

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———dnspython is a DNS toolkit for Python. Prior to version 2.9.2, the from_text() parser for WKS records does not require the service number to be between 0 and 65535 before using it as a bitmap offset. An attacker-controlled zone file can supply a larger number, causing the service bitmap to grow to an extremely large size through inefficient repeated extension, consuming excessive memory and CPU and potentially terminating the process. Applications are affected only when they parse zone-file text whose record type and rdata are attacker controlled. This issue is fixed in version 2.9.2.5h