Security Advisory

CVE-2025-57804

CVE vulnerability detail — eXtreme Datacenter Security Operations

Published 2025-08-25 21:04:52

Last updated 2025-11-03 18:13:44

Assigner GitHub_M

State PUBLISHED

Description

h2 is a pure-Python implementation of a HTTP/2 protocol stack. Prior to version 4.3.0, an HTTP/2 request splitting vulnerability allows attackers to perform request smuggling attacks by injecting CRLF characters into headers. This occurs when servers downgrade HTTP/2 requests to HTTP/1.1 without properly validating header names/values, enabling attackers to manipulate request boundaries and bypass security controls. This issue has been patched in version 4.3.0.

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