Low 2.1Published Oct 26, 2026

CVE-2026-116578Tornado: Open redirect in RedirectHandler via protocol-relative URLs

Updated under an hour ago (Oct 29, 2026, 11:30 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Tornado is a Python web framework and asynchronous networking library. Prior to 6.6, tornado.web.RedirectHandler URL templates can place regex-capture substitutions where crafted request paths change the redirect scheme or network location. Affected placements include substitutions at the start of a path, directly after a fixed host, or at the beginning of the template, including protocol-relative, absolute, backslash, encoded, host-extension, and user-info variants interpreted by browsers as attacker-controlled destinations. Static templates and substitutions after a fixed host followed by a slash are not affected. An attacker can use the resulting open redirect on the application's domain for phishing. This issue is fixed in version 6.6.

CVSS: 2.1 LOW (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
Weakness (CWE): CWE-601
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 26, 2026
First seen by InfoSec Signals: Oct 26, 2026

Affected products

Affected products

tornadoweb tornado tornadoweb:tornado (from the name)	before 6.6	CNA record

References

References

https://github.com/tornadoweb/tornado/security/advisories/GHSA-pw9p-v7r6-gx4p	x-refsource-confirm
https://github.com/tornadoweb/tornado/pull/3786	x-refsource-misc
https://github.com/tornadoweb/tornado/commit/940ea725bdd9bc68231d68a105eef17ea6e11233	x-refsource-misc
https://github.com/tornadoweb/tornado/commit/cc75ab0eb3af459c714895a49f682ad354f50117	x-refsource-misc
https://github.com/tornadoweb/tornado/commit/ccb6a2e5482f17997efd4a74b8200d5b4babc035	x-refsource-misc
https://github.com/tornadoweb/tornado/releases/tag/v6.6.0	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.