CVE-2023-38697
MediumCVSS 5.8Exploitation Probability (EPSS)
Low risk46th percentile - higher than 46% of all known CVEs
Summary
CVE-2023-38697 affects the HTTP/1 protocol implementation in the protocol-http1 library, which does not comply with RFC 9112 specifications regarding Content-Length and chunk size headers. Improper acceptance of header values can lead to desynchronization when forwarding through multiple HTTP parsers, creating risks of HTTP request smuggling and firewall bypassing.
Risk Assessment
Organizations may be vulnerable to HTTP request smuggling attacks, potentially leading to unauthorized access to systems and data leakage. Additionally, the ability to bypass firewalls increases the risk of data exfiltration.
Recommendation
It is recommended to update the protocol-http1 library to version v0.15.1 to mitigate this vulnerability. Monitoring HTTP traffic for potential smuggling attempts is also advised.
Original NVD description (English source)
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.