The HTTP/2 implementation in HAProxy before 2.0.10 mishandles headers, as demonstrated by carriage return (CR, ASCII 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII 0x0), aka Intermediary Encapsulation Attacks.
Created haproxy tracking bugs for this issue:
Affects: fedora-all [bug 1777585]
Support for HTTP/2 protocol was added to haproxy in version 1.8, therefore previous versions are not affected by this flaw.
The version of haproxy shipped in OpenShift Container Platform 4 contains the vulnerable code, however exploitation requires setting ROUTER_USE_HTTP2 in the OpenShift Ingress Operator, which is not currently possible. The impact of this vulnerability is therefore reduced in OpenShift Container Platform 4 to Low.