CVE-2021-21299 describes a request smuggling vulnerability in the hyper HTTP server library for Rust, affecting versions prior to 0.13.10 and 0.14.3. This flaw arises from hyper incorrectly processing HTTP/1.1 requests with multiple transfer-encoding headers, leading to a desync attack when an upstream HTTP proxy interprets the request payload boundary differently. The vulnerability carries a CVSS score of 8.1 (HIGH), indicating a severe impact with high confidentiality, integrity, and availability risks, though it requires a high attack complexity due to specific environmental conditions (an upstream proxy and HTTP/1.1). Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 0.12.0, < 0.13.10CPE matchmatch criteria | cpe:2.3:a:hyper:hyper:*:*:*:*:*:rust:*:* | ||
>= 0.14.0, < 0.14.3CPE matchmatch criteria | cpe:2.3:a:hyper:hyper:*:*:*:*:*:rust:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
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The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.