CVE-2023-54397 PUBLISHED

Tornado before 6.3.3 HTTP Request Smuggling via Content-Length

Assigner: VulnCheck
Reserved: 15.09.2026 Published: 15.09.2026 Updated: 15.09.2026

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 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
CVSS Score: 9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	Low
Attack Complexity	High	Integrity	High	Integrity	High
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
CVSS Score: 7.5

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

CVSS 3.1

Product Status

Vendor	tornadoweb
Product	tornado
Versions	Default: unaffected affected from 0 to 6.3.3 (excl.) Version 6.3.3 is unaffected

Credits

kenballus reporter

References

Problem Types

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') CWE