CVE-2021-21299
Published: 11 February 2021
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.
Priority
Status
Package | Release | Status |
---|---|---|
rust-hyper Launchpad, Ubuntu, Debian |
bionic |
Does not exist
|
focal |
Needs triage
|
|
groovy |
Does not exist
|
|
hirsute |
Ignored
(end of life)
|
|
impish |
Ignored
(end of life)
|
|
jammy |
Does not exist
|
|
kinetic |
Ignored
(end of life, was needs-triage)
|
|
lunar |
Ignored
(end of life, was needs-triage)
|
|
mantic |
Needs triage
|
|
trusty |
Does not exist
|
|
upstream |
Needs triage
|
|
xenial |
Does not exist
|
Severity score breakdown
Parameter | Value |
---|---|
Base score | 8.1 |
Attack vector | Network |
Attack complexity | High |
Privileges required | None |
User interaction | None |
Scope | Unchanged |
Confidentiality | High |
Integrity impact | High |
Availability impact | High |
Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
References
- https://github.com/hyperium/hyper/security/advisories/GHSA-6hfq-h8hq-87mf
- https://rustsec.org/advisories/RUSTSEC-2021-0020.html
- https://crates.io/crates/hyper
- https://github.com/hyperium/hyper/commit/8f93123efef5c1361086688fe4f34c83c89cec02
- https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn
- https://www.cve.org/CVERecord?id=CVE-2021-21299
- NVD
- Launchpad
- Debian