CVE-2023-54397

Tornado before 6.3.3 HTTP Request Smuggling via Content-Length

HIGH
7.5
CVSS Score
Published: September 15, 2026 at 03:17 PM UTC
Updated: September 17, 2026 at 03:16 PM UTC
1 product affected across 1 vendorTornado

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.3.3
Vendor states this is fixed in 6.3.3 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-444

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