Name: CVE-2023-54397: Inconsistent Interpretation of HTTP Requests
Creator: Rapid7
Published: 2026-09-15T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2023-54397, CWE-444, CVSS 7.5, EPSS 0.00377

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.

CVSS Details

CVSS 4.0 Base Score: 9 (CRITICAL)
CVSS 4.0 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/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)
CVSS 3.1 Base Score: 7.5
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Debian	—	Upgrade python-tornado	Sep 17, 2026	Sep 15, 2026
Redhat_linux	—	No solution exists	Sep 30, 2026	Sep 15, 2026
Ubuntu	—	Upgrade python3-tornadoUpgrade python3-tornado (Ubuntu Pro)	Oct 22, 2026	Sep 15, 2026

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CVSS Details

Covered by Rapid7

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