The am_read_post_data function in mod_auth_mellon before 0.11.1 does not check if the ap_get_client_block function returns an error, which allows remote attackers to cause a denial of service (segmentation fault and process crash) via a crafted POST data.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.