Tornado: Open redirect in RedirectHandler via protocol-relative URLs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-116578
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-26 21:18:14 UTC
Updated2026-10-26 21:18:15 UTC
DescriptionTornado 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.

Risk And Classification

Primary CVSS: v4.0 2.1 LOW from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-601 | CWE-601 CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary2.1LOWCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/C...
4.0CNADECLARED2.1LOWCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
Active
Confidentiality
None
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
Low
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Tornadoweb Tornado affected < 6.6 Not specified

References

ReferenceSourceLinkTags
github.com/tornadoweb/tornado/commit/ccb6a2e5482f17997efd4a74b8200d5b4ba... [email protected] github.com
github.com/tornadoweb/tornado/commit/cc75ab0eb3af459c714895a49f682ad354f... [email protected] github.com
github.com/tornadoweb/tornado/security/advisories/GHSA-pw9p-v7r6-gx4p [email protected] github.com
github.com/tornadoweb/tornado/commit/940ea725bdd9bc68231d68a105eef17ea6e... [email protected] github.com
github.com/tornadoweb/tornado/releases/tag/v6.6.0 [email protected] github.com
github.com/tornadoweb/tornado/pull/3786 [email protected] github.com
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