CVEvulnerability

CVE-2026-39963

6.9 MEDIUM Published 2026-04-15 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-04-15
Last modified
2026-10-26
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
Weaknesses
CWE-565

Description

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.

Affected configurations

• s9y serendipity (< 2.6.0) • s9y serendipity 2.6.0

Related

Weakness · CWE (1)

  • CWE-565 Reliance on Cookies without Validation and Integrity Checking weakness

References