GHSA-pr2v-jx2c-wg9f: tornado (CVE-2025-67724)

Package	Ecosystem	Affected	Fixed in
tornado	PyPI	<6.5.3	6.5.3

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Tornado versions before 6.5.3 are vulnerable to header injection and reflected cross-site scripting through the `reason` argument of `RequestHandler.set_status` and `tornado.web.HTTPError`. A remote attacker can exploit this only if the application passes attacker-controlled data as `reason`, which can then inject headers or run JavaScript in a victim's browser on the default error page. Upgrade to Tornado 6.5.3 or newer. Until then, avoid passing untrusted data as `reason`, and use `log_message` for custom error text in HTTPError.

Written 5 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
5.4	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0024, the 15th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:42 UTC First seen by agentprime
31 Oct 2026, 14:42 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.