CVE-2023-54397

Tornado before 6.3.3 HTTP Request Smuggling via Content-Length

Published Sep 15, 2026 CVSS 4.0 · 9 Critical EPSS < 1% KEV · Not listed
Description
Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Content-Length headers accepting non-standard characters. Attackers can send crafted HTTP requests with these characters to bypass proxy validation and smuggle requests when deployed behind certain proxies.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8952-1 Tornado vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Tornado before 6.3.3 contains an HTTP request smuggling vulnerability due to improper parsing of Content-Length headers accepting non-standard characters. Attackers can send crafted HTTP requests with these characters to bypass proxy validation and smuggle requests when deployed behind certain proxies.
Title Tornado before 6.3.3 HTTP Request Smuggling via Content-Length
First Time appeared Tornadoweb
Tornadoweb tornado
Weaknesses CWE-444
CPEs cpe:2.3:a:tornadoweb:tornado:*:*:*:*:*:*:*:*
Vendors & Products Tornadoweb
Tornadoweb tornado
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N'}

cvssV4_0

{'score': 9, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 17, 2026, 2:48 PM
Reserved
Sep 15, 2026, 11:12 AM
Status
Deferred
Published
Sep 15, 2026, 4:17 PM
Modified
Sep 17, 2026, 3:16 PM
Severity
Critical
Public date
Sep 15, 2026, 3:17 PM