CVE-2021-21299

hyper is an open-source HTTP library for Rust (crates.io). In hyper from version 0.12.0 and before versions 0.13.10 and 0.14.3 there is a vulnerability that can enable a request smuggling attack. The HTTP server code had a flaw that incorrectly understands some requests with multiple transfer-encoding headers to have a chunked payload, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that understands the request payload boundary differently can result in "request smuggling" or "desync attacks". To determine if vulnerable, all these things must be true: 1) Using hyper as an HTTP server (the client is not affected), 2) Using HTTP/1.1 (HTTP/2 does not use transfer-encoding), 3) Using a vulnerable HTTP proxy upstream to hyper. If an upstream proxy correctly rejects the illegal transfer-encoding headers, the desync attack cannot succeed. If there is no proxy upstream of hyper, hyper cannot start the desync attack, as the client will repair the headers before forwarding. This is fixed in versions 0.14.3 and 0.13.10. As a workaround one can take the following options: 1) Reject requests that contain a `transfer-encoding` header, 2) Ensure any upstream proxy handles `transfer-encoding` correctly.

Link	Resource
https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn	Third Party Advisory
https://github.com/hyperium/hyper/commit/8f93123efef5c1361086688fe4f34c83c89cec02	Patch Third Party Advisory
https://crates.io/crates/hyper	Product Third Party Advisory
https://github.com/hyperium/hyper/security/advisories/GHSA-6hfq-h8hq-87mf	Third Party Advisory
https://rustsec.org/advisories/RUSTSEC-2021-0020.html	Third Party Advisory

Configuration 1

cpe:2.3:a:hyper:hyper:*:*:*:*:*:rust:*:* cpe:2.3:a:hyper:hyper:*:*:*:*:*:rust:*:*

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Published : 2021-02-11 06:15

Updated : 2021-02-19 06:28

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NVD link : CVE-2021-21299

Mitre link : CVE-2021-21299

No products.

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')