CVE-2021-32715

CVE-2021-32715 is a medium-severity vulnerability in the hyper HTTP library for Rust, affecting all versions prior to 0.14.10 when built with rustc v1.5.0 or newer. The flaw allows hyper's HTTP/1 server to incorrectly parse and accept requests with a plus sign prefixed Content-Length header, which should be rejected. This misparsing, when combined with an upstream HTTP proxy that forwards such headers without proper handling, can lead to "request smuggling" or "desync attacks." The vulnerability has a CVSS score of 5.3 (Medium) due to its network attack vector and low complexity, potentially resulting in data integrity impacts. There is no evidence of active exploitation, nor are there publicly available exploit tools like Metasploit or ExploitDB entries, and it has received minimal community discussion or media coverage.