CVE-2023-38697CWE-444

protocol-http1 HTTP Request/Response Smuggling vulnerability

Medium · published August 4, 2023

CVSS v3.1
5.8
EPSS
1%
Percentile
54.6
In the wild
Unconfirmed
What it is

protocol-http1 provides a low-level implementation of the HTTP/1 protocol. RFC 9112 Section 7.1 defined the format of chunk size, chunk data and chunk extension. The value of Content-Length header should be a string of 0-9 digits, the chunk size should be a string of hex digits and should split from chunk data using CRLF, and the chunk extension shouldn't contain any invisible character. However, Falcon has following behaviors while disobey the corresponding RFCs: accepting Content-Length header values that have `+` prefix, accepting Content-Length header values that written in hexadecimal with `0x` prefix, accepting `0x` and `+` prefixed chunk size, and accepting LF in chunk extension. This behavior can lead to desync when forwarding through multiple HTTP parsers, potentially results in HTTP request smuggling and firewall bypassing. This issue is fixed in `protocol-http1` v0.15.1. There are no known workarounds.

The record
Technical detail
CVSS v3.1
5.8 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00754 · 54.6th percentile
Weakness
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Published
2023-08-04T17:32Z
EPSS history
Timeline
  • 04 AUG 17:32Z
    protocol-http1 HTTP Request/Response Smuggling vulnerability
    cvelistv5