CVE-2023-54397 Tornado - HTTP Request Smuggling

Tornado < 6.3.3 contains an HTTP request smuggling vulnerability caused by improper parsing of Content-Length headers accepting non-standard characters, letting attackers bypass proxy validation and smuggle requests, exploit requires deployment behind certain proxies.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.38% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
HTTP Request Smuggling
Impact
HTTP Request Smuggling
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
Published
15 September 2026
Updated
15 October 2026
Weakness
CWE-444

Vendor fix

Update to version 6.3.3 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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