CVE-2026-116578

Tornado: Open redirect in RedirectHandler via protocol-relative URLs

LOW
2.1
CVSS Score
Published: October 26, 2026 at 08:22 PM UTC
Updated: October 30, 2026 at 03:16 PM UTC
1 product affected across 1 vendorTornado

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Severity
LOW2.1
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

2.1LOWGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-601

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