Home/CVE/Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, the supplied reason
CVE

CVE-2025-67724

Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, the supplied reason

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.

MEDIUM · CVSS 5.4 EPSS 0.00035
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-644Improper Neutralization of HTTP Headers for Scripting Syntax
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
▤

Affected Products & Versions

1
tornadoweb tornado< 6.5.3
▣

Scoring & Timeline

5.4
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 Dec 2025 · 06:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
⚑

Vendor Advisories

30
suse-csafSUSE-SU-2026:1162-1
suse-csafSUSE-SU-2026:1140-1
suse-csafSUSE-SU-2026:1141-1
suse-csafSUSE-SU-2026:1142-1
suse-csafSUSE-SU-2026:1146-1
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/tornadoweb/tornado/commit/9c163aebeaad9e6e7d28bac1f33580eb00b0e421Patch
https://github.com/tornadoweb/tornado/releases/tag/v6.5.3Release Notes
https://github.com/tornadoweb/tornado/security/advisories/GHSA-pr2v-jx2c-wg9fMitigationVendor Advisory
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