CVE-2025-67724

5.4 MEDIUM 0.2% exploit odds Fix listed XSS Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-12-12 06:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-07 20:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 5.4 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-12-12 06:15 UTC
Last modified: 2026-10-07 20:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-79 · Cross-site scripting
Record status: Analyzed

Affected

Tornadoweb Tornado < 6.5.3

Attack profile CVSS 3.1 · 5.4

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-67724.md and follow it. Check whether this project is affected by CVE-2025-67724. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record