CVE-2023-54397

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductTornado

PublishedSep 15, 2026

First seenSep 15, 2026

Weakness typeCWE-444CWE-444

How to fix

Update

tornado6.3.3 or later

Vendor advisories

github.com/tornadoweb/tornado/security/advisories/GHSA-qppv-j76h-2rpx

Affected products

Product	Affected versions	Fixed in
tornadoPyPI	v < 6.3.3	6.3.3

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