Inefficient Algorithmic Complexity Affecting tornado package, versions [,6.6)
Threat Intelligence
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-21755374
- published27 Oct 2026
- disclosed26 Oct 2026
- creditDaniel Coles
Introduced: 26 Oct 2026
NewCVE-2026-116577 (opens in a new tab)How to fix?
Upgrade tornado to version 6.6 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 Inefficient Algorithmic Complexity via the parse_line method in tornado/httputil.py, which supports obsolete HTTP header line folding. An attacker can send HTTP requests containing folded header lines to trigger quadratic time complexity in header parsing, causing a crash.