An out-of-bounds read in dns_validate_dns_response in dns.c was discovered in HAProxy through 1.8.14. Due to a missing check when validating DNS responses, remote attackers might be able read the 16 bytes corresponding to an AAAA record from the non-initialized part of the buffer, possibly accessing anything that was left on the stack, or even past the end of the 8193-byte buffer, depending on the value of accepted_payload_size.

An issue was discovered in dns.c in HAProxy through 1.8.14. In the case of a compressed pointer, a crafted packet can trigger infinite recursion by making the pointer point to itself, or create a long chain of valid pointers resulting in stack exhaustion.

A flaw was discovered in the HPACK decoder of HAProxy, before 1.8.14, that is used for HTTP/2. An out-of-bounds read access in hpack_valid_idx() resulted in a remote crash and denial of service.

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 proto_http.c check_request_for_cacheability function.

An issue was discovered in HAProxy before 1.8.8. The incoming H2 frame length was checked against the max_frame_size setting instead of being checked against the bufsize. The max_frame_size only applies to outgoing traffic and not to incoming, so if a large enough frame size is advertised in the SETTINGS frame, a wrapped frame will be defragmented into a temporary allocated buffer where the second fragment may overflow the heap by up to 16 kB. It is very unlikely that this can be exploited for code execution given that buffers are very short lived and their addresses not realistically predictable in production, but the likelihood of an immediate crash is absolutely certain.

HAProxy statistics in openstack-tripleo-image-elements are non-authenticated over the network.

HAproxy 1.6.x before 1.6.6, when a deny comes from a reqdeny rule, allows remote attackers to cause a denial of service (uninitialized memory access and crash) or possibly have unspecified other impact via unknown vectors.

The buffer_slow_realign function in HAProxy 1.5.x before 1.5.14 and 1.6-dev does not properly realign a buffer that is used for pending outgoing data, which allows remote attackers to obtain sensitive information (uninitialized memory contents of previous requests) via a crafted request.

Multiple integer overflows in the http_request_forward_body function in proto_http.c in HAProxy 1.5-dev23 before 1.5.4 allow remote attackers to cause a denial of service (crash) via a large stream of data, which triggers a buffer overflow and an out-of-bounds read.

HAProxy 1.4 before 1.4.24 and 1.5 before 1.5-dev19, when configured to use hdr_ip or other "hdr_*" functions with a negative occurrence count, allows remote attackers to cause a denial of service (negative array index usage and crash) via an HTTP header with a certain number of values, related to the MAX_HDR_HISTORY variable.