Improper Handling of Highly Compressed Data (Data Amplification) Affecting tornado package, versions [,6.5.9)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-TORNADO-20415626
- published3 Oct 2026
- disclosed1 Oct 2026
- creditUnknown
Introduced: 1 Oct 2026
NewCVE-2026-103262 (opens in a new tab)How to fix?
Upgrade tornado to version 6.5.9 or higher.
Overview
tornado is a Python web framework and asynchronous networking library, originally developed at FriendFeed.
Affected versions of this package are vulnerable to Improper Handling of Highly Compressed Data (Data Amplification) via curl_httpclient.py in CurlAsyncHTTPClient, which passes every chunk libcurl produces to IOLoop.add_callback without bounding the amount of buffered data. When decompress_response is enabled, an attacker-controlled server can send a decompression bomb - a small compressed payload that expands to gigabytes - causing all decompressed chunks to accumulate in the IOLoop's callback queue and exhausting process memory. Additionally, without a streaming_callback, curl_httpclient had no max_body_size limit, allowing a server to buffer arbitrarily large response bodies.