Nginx Upstream returning 400 Bad Request if null character is being passed in the request as part of uri or query params.

Is there a way Null Character can be removed from request before proxying it to upstream.

Its only known from access logs that null character is being passed in request as \x00 and causing the failure

How to identify the Null Character and remove it ?

Tried below options but its not able to identify the null character

if ($args ~* (.*)(\x00)(.*)) {
set $args $1$3;
}


Nginx returning below error

Error Log

2020/06/25 20:20:43 [info] 19838#19838: *11985 client sent invalid request while reading client request line, client: 10.49.120.61, server: test.com, request: "HEAD /folder/Test.m3u8?uid=abc123 HTTP/1.0"


Access log

10.49.120.61 | - | test.com | [25/Jun/2020:20:20:43 +0530] | - | "HEAD /folder/Test.m3u8?uid=abc123\x00 HTTP/1.0" | 400 | 0 | "-" | "-" | 0.001 | - | - | - | "- - - -" | http | - | -| "-"