CVE - CVE-2021-21299

CVE-ID
CVE-2021-21299	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
CONFIRM:https://github.com/hyperium/hyper/security/advisories/GHSA-6hfq-h8hq-87mf URL:https://github.com/hyperium/hyper/security/advisories/GHSA-6hfq-h8hq-87mf MISC:https://rustsec.org/advisories/RUSTSEC-2021-0020.html MISC:https://crates.io/crates/hyper URL:https://crates.io/crates/hyper MISC:https://github.com/hyperium/hyper/commit/8f93123efef5c1361086688fe4f34c83c89cec02 URL:https://github.com/hyperium/hyper/commit/8f93123efef5c1361086688fe4f34c83c89cec02 MISC:https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn URL:https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn
Assigning CNA
GitHub (maintainer security advisories)
Date Record Created
20201222	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20201222)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
This is an record on the CVE List, which provides common identifiers for publicly known cybersecurity vulnerabilities.
Search CVE Using Keywords: You can also search by reference using the CVE Reference Maps.
For More Information: CVE Request Web Form (select "Other" from dropdown)