CVE-2026-93574: netty HTTP Request/Response Smuggling

Vulnerability summary

CVE-2026-93574 is a medium (CVSS 6.5) HTTP Request/Response Smuggling vulnerability in netty. EPSS estimates a 1.35% chance of exploitation in the next 30 days, higher than 71.1% of scored vulnerabilities.

Timeline

1. 18-09-2026
   PublishedVulnerability first disclosed.
2. 15-10-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in Netty's `netty-codec-http` component. A remote attacker could exploit this vulnerability by sending a specially crafted HTTP/1.1 chunk-size token that includes post-digit whitespace. This incorrect parsing of the chunk size can lead to HTTP request smuggling. This allows an attacker to bypass security controls or access unauthorized resources in proxy/backend deployments.

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.