Tornado: Open redirect via triple-slash redirect paths

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-126347
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-12 22:19:19 UTC
Updated2026-11-12 22:19:19 UTC
DescriptionTornado is a Python web framework and asynchronous networking library. In versions through 6.6.0, applications using  tornado.web.RedirectHandler  with URL templates that allow attacker-controlled substitutions to influence the destination can be vulnerable to an open redirect using three or more leading slashes. Differences between Python’s URL parsing and browser URL interpretation allow a crafted destination to redirect a user to an attacker-controlled host. The remediation for CVE-2026-116578 in version 6.6.0 did not fully address this case. This issue is fixed in version 6.6.1.

Risk And Classification

Primary CVSS: v3.1 3.1 LOW from [email protected]

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

Problem Types: CWE-601 | CWE-601 CWE-601: URL Redirection to Untrusted Site

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.1LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
3.1CNADECLARED3.1LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Tornadoweb Tornado affected < 6.6.1 Not specified

References

ReferenceSourceLinkTags
github.com/tornadoweb/tornado/commit/c503241622c0efe7c40110d89834ce8b7fe... [email protected] github.com
github.com/tornadoweb/tornado/security/advisories/GHSA-5cjw-f85j-cv6r [email protected] github.com
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