Apache :: Capturing Internal Apache Errors Return Custom HTTP Status

Server Version: Apache/2.2.22 (Unix)

On our production service, we've been getting numerous malformed POST requests to some of our CGI scripts that are showing up as 500 errors in our logs. They are malformed in the sense that the actual content length doesn't match the Content-Length specified in the request.

Here's the most trivial example I can come up with that reproduces the problem for us:

POST /some_valid_alias HTTP/1.1
Host: example.org
User-Agent: Arbitrary/1.0
Content-Type: multipart/form-data; boundary=---------------------------41184676334
Content-Length: 769
-----------------------------41184676334

In addition to the 500 error in the access log, we see the corresponding error in the error log:

(70014)End of file found: Error reading request entity data

Based on the nature of the POST request and the error response, it does appear that Apache is doing the right thing here.

The POST never actually makes it as far as the script being targeted (/some_valid_alias in the above example); in other words, Apache returns 500 to the client, writes the error to the error log and never executes the script.

Is there a way to capture/avoid internal Apache errors like 70014, and return some other HTTP status besides 500 (like 403)? It's particularly annoying in our case, because our server sends us an email for all 500 errors.

So far, our best "defense" against these 500 errors is to disallow POST for these aliases, which normally just ignore the POST data anyway (when the request is not malformed):

RewriteCond %{REQUEST_METHOD} ^POST$
RewriteRule ^/(some_valid_alias)(.*)$ $1$2 [R]

But this won't work for all our scripts, because in some cases we do want to permit POST.