{"cve":"CVE-2021-32715","nvd":{"published":"2021-07-07T20:15:08.750","modified":"2026-06-17T03:53:29.050","status":"Modified","description":"hyper is an HTTP library for rust. hyper's HTTP/1 server code had a flaw that incorrectly parses and accepts requests with a `Content-Length` header with a prefixed plus sign, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that doesn't parse such `Content-Length` headers, but forwards them, can result in \"request smuggling\" or \"desync attacks\". The flaw exists in all prior versions of hyper prior to 0.14.10, if built with `rustc` v1.5.0 or newer. The vulnerability is patched in hyper version 0.14.10. Two workarounds exist: One may reject requests manually that contain a plus sign prefix in the `Content-Length` header or ensure any upstream proxy handles `Content-Length` headers with a plus sign prefix.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-444"],"references":["https://github.com/hyperium/hyper/security/advisories/GHSA-f3pg-qwvg-p99c","https://github.com/rust-lang/rust/pull/28826/commits/123a83326fb95366e94a3be1a74775df4db97739","https://github.com/hyperium/hyper/security/advisories/GHSA-f3pg-qwvg-p99c","https://github.com/rust-lang/rust/pull/28826/commits/123a83326fb95366e94a3be1a74775df4db97739"],"products":["hyper:hyper"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-32715","score":0.01126,"percentile":0.66311,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-f3pg-qwvg-p99c","url":"https://osv.dev/vulnerability/GHSA-f3pg-qwvg-p99c","summary":"Lenient Parsing of Content-Length Header When Prefixed with Plus Sign","modified":"2026-09-10T03:49:06.257461312Z","packages":[{"ecosystem":"crates.io","name":"hyper","purl":"pkg:cargo/hyper","ranges":["<0.14.10"],"fixed":["0.14.10"]}]},{"id":"RUSTSEC-2021-0078","url":"https://osv.dev/vulnerability/RUSTSEC-2021-0078","summary":"Lenient `hyper` header parsing of `Content-Length` could allow request smuggling","modified":"2026-10-12T18:00:03.463487342Z","packages":[{"ecosystem":"crates.io","name":"hyper","purl":"pkg:cargo/hyper","ranges":[">=0.0.0-0 <0.14.10"],"fixed":["0.14.10"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}