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GHSA-qppv-j76h-2rpx
No affected components available
Summary
Tornado interprets -, +, and _ in chunk length and Content-Length values, which are not allowed by the HTTP RFCs. This can result in request smuggling when Tornado is deployed behind certain proxies that interpret those non-standard characters differently. This is known to apply to older versions of haproxy, although the current release is not affected.
Details
Tornado uses the int constructor to parse the values of Content-Length headers and chunk lengths in the following locations:
tornado/http1connection.py:445
self._expected_content_remaining = int(headers["Content-Length"])
tornado/http1connection.py:621
content_length = int(headers["Content-Length"]) # type: Optional[int]
tornado/http1connection.py:671
chunk_len = int(chunk_len_str.strip(), 16)
Because int("0_0") == int("+0") == int("-0") == int("0"), using the int constructor to parse and validate strings that should contain only ASCII digits is not a good strategy.
Measures severity based on intrinsic characteristics of the vulnerability, independent of environment.
No exploitation activity has been observed at this time. Continue routine monitoring.
Probability that this vulnerability will be exploited in the wild within the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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