Bug 63871

Summary:	Header edit bypassed after multiple merge
Product:	Apache httpd-2	Reporter:	t3kk4m
Component:	mod_headers	Assignee:	Apache HTTPD Bugs Mailing List <bugs>
Status:	NEW ---
Severity:	normal
Priority:	P2
Version:	2.4.6
Target Milestone:	---
Hardware:	HP
OS:	Linux
Attachments:	Accurate example configuration snipped

Description t3kk4m 2019-10-22 00:39:27 UTC

Created attachment 36851 [details]
Accurate example configuration snipped

> Environment
Binaries are installed on a CentOS 7 (rel. 1905 - x86_64) on a EC2 vm (official hvm AMI) via stock yum repositories (no third party repos are configured, except from MariaDB 10.2 repo for clients).

> Alerts
Service is apparently running without any issue. Logging is set in VirtualHost context and includes INFO level. 

> Configuration details
For your discretion, i must advice you that configuration is built through extensive use of mod_macro from virtualhost context and above, but i'm quite sure it's not involved. Indeed, misbehaving directives are all configured by the same macro, which is called once for each VirtualHost (example snippet is "macro expanded") and resulting configuration is triggered correctly.

> Unexpected Behavior
Despite several trials of "Header edit", pattern is never rewritten.
It looks like Header edit is not able to match commas (added by Header merge directives). I suspect its input has been split upon separating commas by a preceding parser or it's fed by an outdated or null header referral.