CVE-2021-32715 Lenient Parsing of Content-Length Header When Prefixed with Plus Sign

2021-07-0720:05:11

CWE-444

GitHub_M

www.cve.org

3.1 Low

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

5.6 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

38.8%

JSON

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.

CNA Affected

[
  {
    "product": "hyper",
    "vendor": "hyperium",
    "versions": [
      {
        "status": "affected",
        "version": "< 0.14.10"
      }
    ]
  }
]