examples/consumer/common.php in JanRain PHP OpenID library (aka php-openid) improperly checks the openid.realm parameter against the SERVER_NAME element in the SERVER superglobal array, which might allow remote attackers to hijack the authentication of arbitrary users via vectors involving a crafted HTTP Host header.

JanRain PHP OpenID library (aka php-openid) 2.2.2 allows remote attackers to obtain sensitive information via a direct request to a .php file, which reveals the installation path in an error message, as demonstrated by Auth/Yadis/Yadis.php and certain other files.

Auth/Yadis/XML.php in PHP OpenID Library 2.2.2 and earlier allows remote attackers to read arbitrary files, send HTTP requests to intranet servers, or cause a denial of service (CPU and memory consumption) via XRDS data containing an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.