HTTP Request Smuggling Affecting rust-hyper package, versions <0.14.19-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.32% (71st percentile)

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  • Snyk IDSNYK-DEBIAN12-RUSTHYPER-2937980
  • published7 Feb 2021
  • disclosed11 Feb 2021

Introduced: 7 Feb 2021

CVE-2021-21299  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade Debian:12 rust-hyper to version 0.14.19-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rust-hyper package and not the rust-hyper package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1