Description
Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, the supplied reason phrase is used unescaped in HTTP headers (where it could be used for header injection) or in HTML in the default error page (where it could be used for XSS) and can be exploited by passing untrusted or malicious data into the reason argument. Used by both RequestHandler.set_status and tornado.web.HTTPError, the argument is designed to allow applications to pass custom "reason" phrases (the "Not Found" in HTTP/1.1 404 Not Found) to the HTTP status line (mainly for non-standard status codes). This issue is fixed in version 6.5.3.
Problem types
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-644: Improper Neutralization of HTTP Headers for Scripting Syntax
Product status
References
github.com/...ornado/security/advisories/GHSA-pr2v-jx2c-wg9f
github.com/...ommit/9c163aebeaad9e6e7d28bac1f33580eb00b0e421
github.com/tornadoweb/tornado/releases/tag/v6.5.3
Data based on CVE®. Copyright © 1999-2025, The MITRE Corporation. All rights reserved.
