Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the serendipity_setCookie() function in include/functions_config.inc.php uses $_SERVER['HTTP_HOST'] without validation as the domain parameter of setcookie(). An attacker who can influence the Host header at login time, such as via MITM, reverse proxy misconfiguration, or load balancer manipulation, can force authentication cookies including session tokens and auto-login tokens to be scoped to an attacker-controlled domain. This enables session fixation, token leakage to attacker-controlled infrastructure, and privilege escalation if an admin logs in under a poisoned Host header. This issue has been fixed in version 2.6.0.
Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the email sending functionality in include/functions.inc.php inserts $_SERVER['HTTP_HOST'] directly into the Message-ID SMTP header without validation, and the existing sanitization function serendipity_isResponseClean() is not called on HTTP_HOST before embedding it. An attacker who can control the Host header during an email-triggering action such as comment notifications or subscription emails can inject arbitrary SMTP headers into outgoing emails. This enables identity spoofing, reply hijacking via manipulated Message-ID threading, and email reputation abuse through the attacker's domain being embedded in legitimate mail headers. This issue has been fixed in version 2.6.0.
Serendipity before 2.3.4 on Windows allows remote attackers to execute arbitrary code because the filename of a renamed file may end with a dot. This file may then be renamed to have a .php filename.
serendipity_moveMediaDirectory in Serendipity 2.0.3 allows remote attackers to upload and execute arbitrary PHP code because it mishandles an extensionless filename during a rename, as demonstrated by "php" as a filename.
Serendipity before 2.1.5 has XSS via EXIF data that is mishandled in the templates/2k11/admin/media_choose.tpl Editor Preview feature or the templates/2k11/admin/media_items.tpl Media Library feature.
Open redirect vulnerability in comment.php in Serendipity through 2.0.5 allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via a URL in the HTTP Referer header.
include/functions_installer.inc.php in Serendipity through 2.0.5 is vulnerable to File Inclusion and a possible Code Execution attack during a first-time installation because it fails to sanitize the dbType POST parameter before adding it to an include() call in the bundled-libs/serendipity_generateFTPChecksums.php file.