A flaw was found in the way haproxy processed certain HTTP/2 request packets. An attacker could send crafted HTTP/2 request packets which cause memory corruption, leading to a crash or potential remote arbitrary code execution with the permissions of the user running haproxy.

An out-of-bounds read issue was discovered in the HTTP/2 protocol decoder in HAProxy 1.8.x and 1.9.x through 1.9.0 which can result in a crash. The processing of the PRIORITY flag in a HEADERS frame requires 5 extra bytes, and while these bytes are skipped, the total frame length was not re-checked to make sure they were present in the frame.

Incorrect caching of responses to requests including an Authorization header in HAProxy 1.8.0 through 1.8.9 (if cache enabled) allows attackers to achieve information disclosure via an unauthenticated remote request, related to the protohttp.c checkrequestforcacheability function.