title: Lenient Parsing of Content-Length Header When Prefixed with Plus Sign
description: hyper is an HTTP library for rust. hyper's HTTP/1 server code had a flaw that incorrectly parses and accepts requests with a `Content-Length` header with a prefixed plus sign, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that doesn't parse such `Content-Length` headers, but forwards them, can result in "request smuggling" or "desync attacks". The flaw exists in all prior versions of hyper prior to 0.14.10, if built with `rustc` v1.5.0 or newer. The vulnerability is patched in hyper version 0.14.10. Two workarounds exist: One may reject requests manually that contain a plus sign prefix in the `Content-Length` header or ensure any upstream proxy handles `Content-Length` headers with a plus sign prefix.
problem types: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')
affected:
{
product: hyper
vendor: hyperium
versions:
status: affected, version: < 0.14.10
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 3.1
baseSeverity: LOW
confidentialityImpact: LOW
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
version: 3.1
]