CVE-2025-67724Network attack vector

Cross-site scripting and header injection via reason

Published Dec 12, 2025 · Updated Dec 12, 2025

Cross-site scripting and header injection in Tornado before 6.5.3 allow remote attackers to inject browser scripts or HTTP headers. RequestHandler.set_status and tornado.web.HTTPError pass an application-supplied reason phrase into the status line without validation and into the default error page without HTML escaping. Exploitation requires an application to place untrusted data in reason and a victim to view the resulting error page; successful XSS executes JavaScript in that victim's browser.

CVSS severity5.4
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting and header injection in Tornado before 6.5.3 allow remote attackers to inject browser scripts or HTTP headers. RequestHandler.set_status and tornado.web.HTTPError pass an application-supplied reason phrase into the status line without validation and into the default error page without HTML escaping. Exploitation requires an application to place untrusted data in reason and a victim to view the resulting error page; successful XSS executes JavaScript in that victim's browser.

The record

CVE
CVE-2025-67724
Published
Dec 12, 2025
Updated
Dec 12, 2025
Vendor
tornadoweb
Product
Tornado
Classifications
CWE-79, CWE-644, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.5.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

tornadoweb · Tornadoversion=< 6.5.3

Published CVSS scores

5.4GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-644Improper Neutralization of HTTP Headers for Scripting Syntax
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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