Package Instance

AIOHTTP vulnerable to  denial of service through large payloads
### Summary
A request can be crafted in such a way that an aiohttp server's memory fills up uncontrollably during processing.

### Impact
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.

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Patch: https://github.com/aio-libs/aiohttp/commit/b7dbd35375aedbcd712cbae8ad513d56d11cce60

AIOHTTP has unicode match groups in regexes for ASCII protocol elements
### Summary

The parser allows non-ASCII decimals to be present in the Range header.

### Impact

There is no known impact, but there is the possibility that there's a method to exploit a request smuggling vulnerability.

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Patch: https://github.com/aio-libs/aiohttp/commit/c7b7a044f88c71cefda95ec75cdcfaa4792b3b96

AIOHTTP is vulnerable to HTTP Request/Response Smuggling through incorrect parsing of chunked trailer sections
### Summary
The Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request.

### Impact
If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections.

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Patch: https://github.com/aio-libs/aiohttp/commit/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a

AIOHTTP vulnerable to DoS through chunked messages
### Summary

Handling of chunked messages can result in excessive blocking CPU usage when receiving a large number of chunks.

### Impact

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.

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Patch: https://github.com/aio-libs/aiohttp/commit/dc3170b56904bdf814228fae70a5501a42a6c712
Patch: https://github.com/aio-libs/aiohttp/commit/4ed97a4e46eaf61bd0f05063245f613469700229

aiohttp has a memory leak when middleware is enabled when requesting a resource with a non-allowed method
### Summary

A memory leak can occur when a request produces a `MatchInfoError`. This was caused by adding an entry to a cache on each request, due to the building of each `MatchInfoError` producing a unique cache entry.

### Impact

If the user is making use of any middlewares with `aiohttp.web` then it is advisable to upgrade immediately.

An attacker may be able to exhaust the memory resources of a server by sending a substantial number (100,000s to millions) of such requests.

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Patch: https://github.com/aio-libs/aiohttp/commit/bc15db61615079d1b6327ba42c682f758fa96936

AIOHTTP's unicode processing of header values could cause parsing discrepancies
### Summary
The Python HTTP parser may allow a request smuggling attack with the presence of non-ASCII characters.

### Impact
If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections.

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Patch: https://github.com/aio-libs/aiohttp/commit/32677f2adfd907420c078dda6b79225c6f4ebce0

AIOHTTP's HTTP Parser auto_decompress feature is vulnerable to zip bomb
### Summary
A zip bomb can be used to execute a DoS against the aiohttp server.

### Impact
An attacker may be able to send a compressed request that when decompressed by aiohttp could exhaust the host's memory.

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Patch: https://github.com/aio-libs/aiohttp/commit/2b920c39002cee0ec5b402581779bbaaf7c9138a

AIOHTTP vulnerable to DoS when bypassing asserts
### Summary
When assert statements are bypassed, an infinite loop can occur, resulting in a DoS attack when processing a POST body.

### Impact
If optimisations 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.

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Patch: https://github.com/aio-libs/aiohttp/commit/bc1319ec3cbff9438a758951a30907b072561259

AIOHTTP vulnerable to brute-force leak of internal static file path components
### Summary
Path normalization for static files prevents path traversal, but opens up the ability for an attacker to ascertain the
existence of absolute path components.

### Impact
If an application uses `web.static()` (not recommended for production deployments), it may be possible for an attacker to ascertain the existence of path components.

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Patch: https://github.com/aio-libs/aiohttp/commit/f2a86fd5ac0383000d1715afddfa704413f0711e

AIOHTTP Vulnerable to Cookie Parser Warning Storm
### Summary
Reading multiple invalid cookies can lead to a logging storm.

### Impact
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.

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Patch: https://github.com/aio-libs/aiohttp/commit/64629a0834f94e46d9881f4e99c41a137e1f3326