Bug 2533932 (CVE-2023-54397)

Summary: CVE-2023-54397 python-tornado: Tornado before 6.3.3 HTTP Request Smuggling via Content-Length
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: urgent Docs Contact:
Priority: urgent    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Tornado's HTTP request header parsing logic. When processing incoming HTTP requests, Tornado fails to reject malformed Content-Length headers containing non-standard characters. An unauthenticated remote attacker can exploit this parsing discrepancy when Tornado is deployed behind a front-end proxy or load balancer to cause a request boundary mismatch. This allows the attacker to conduct HTTP request smuggling, bypass proxy-level security controls, and inject unauthorized requests directly into the backend application context.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2542521    
Bug Blocks:    

Description OSIDB Bzimport 2026-09-15 15:51:41 UTC 
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.