CVE-2023-54397

HIGH 7.5

Tornado before 6.3.3 HTTP Request Smuggling via Content-Length

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-444
Vendor	tornadoweb
Product	tornado
Published	Sep 15, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

High

Availability

None

Affected Versions

tornadoweb / tornado

0 < 6.3.3

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/tornadoweb/tornado/security/advisories/GHSA-qppv-j76h-2rpx vulncheck.com: https://www.vulncheck.com/advisories/tornado-before-6.3.3-http-request-smuggling-via-content-length

Credits

🔍 kenballus