---
id: CVE-2025-67724
title: Tornado is a Python web framework and asynchronous networking library
summary: >-
  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 erro…
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'
cwe:
  - CWE-79
  - CWE-644
vendor: tornadoweb
product: tornado
affected:
  - tornado < 6.5.3
patched:
  - tornado 6.5.3
published: '2025-12-12'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T20:10:01.970'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-67724'
references:
  - url: >-
      https://github.com/tornadoweb/tornado/commit/9c163aebeaad9e6e7d28bac1f33580eb00b0e421
    label: security-advisories@github.com
  - url: 'https://github.com/tornadoweb/tornado/releases/tag/v6.5.3'
    label: security-advisories@github.com
  - url: >-
      https://github.com/tornadoweb/tornado/security/advisories/GHSA-pr2v-jx2c-wg9f
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-67724.json
  - url: 'https://access.redhat.com/security/cve/CVE-2025-67724'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2421719'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2025-67724'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-67724'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - osv
  - pip
epss: 0.0024
epssPercentile: 0.15028
aliases:
  - PYSEC-2025-265
  - GHSA-pr2v-jx2c-wg9f
ecosystem: pip
scores:
  nvd: 5.4
  vendor: 5.4
  osv: 6.1
ingestedAt: '2026-07-13T18:58:06.906Z'
---

## Overview

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.

## Affected

- `tornado < 6.5.3`

## Remediation

Upgrade past the affected range:

- `tornado 6.5.3`

## Package advisory (CVE-2025-67724)

Affected packages:

- `tornado < 6.5.3`

Patched in:

- `tornado 6.5.3`

Source: https://osv.dev/vulnerability/PYSEC-2025-265

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: External Secrets Operator for Red Hat OpenShift, external secrets operator for Red Hat OpenShift - Tech Preview, OpenShift Service Mesh 2, OpenShift Service Mesh 3, Red Hat Advanced Cluster Security 4, Red Hat Enterprise Linux 10, … · no fix planned: External Secrets Operator for Red Hat OpenShift, external secrets operator for Red Hat OpenShift - Tech Preview, OpenShift Service Mesh 2, OpenShift Service Mesh 3, … · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-67724.json)