CVE-2023-30536

slim/psr7 is a PSR-7 implementation for use with Slim 4. In versions prior
to 1.6.1 an attacker could sneak in a newline (\n) into both the header
names and values. While the specification states that \r\n\r\n is used to
terminate the header list, many servers in the wild will also accept \n\n.
An attacker that is able to control the header names that are passed to
Slilm-Psr7 would be able to intentionally craft invalid messages, possibly
causing application errors or invalid HTTP requests being sent out with an
PSR-18 HTTP client. The latter might present a denial of service vector if
a remote service’s web application firewall bans the application due to the
receipt of malformed requests. The issue has been patched in version 1.6.1.
There are no known workarounds to this issue. Users are advised to upgrade.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1034580&gt;