Improper Input Validation
guzzlehttp/psr7 is a PSR-7 HTTP message library. Versions prior to 1.8.4 and 2.1.1 are vulnerable to improper header parsing. An attacker could sneak in a new line character and pass untrusted values. The issue is patched in 1.8.4 and 2.1.1. There are currently no known workarounds.
CWE-20 - Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.