CVE-2026-126347
Tornado: Open redirect via triple-slash redirect paths
- Low 3.1
Description
Tornado 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.
Key facts
- Published
- 12 Nov 2026
- Last changed
- 13 Nov 2026
- Assigned by
- GitHub_M
- EPSS
- 0.163% likely to be exploited in the next 30 days, higher than 5.556% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: none; Automatable: no; Technical impact: partial
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 3.1CVSS 3.1, Lowfrom the CNA (GitHub_M)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| tornadoweb | tornado |
|
Timeline
- 12 Nov 2026 Published