6.9

CVE-2026-39963

Exploit

Serendipity: Host Header Injection enables authentication cookie scoping to an attacker-controlled domain

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
S9y ≫ Serendipity Version < 2.6.0
S9y ≫ Serendipity Version2.6.0 Updatebeta1
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.22% 0.128
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 6.9 1.6 4.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
CWE-565 Reliance on Cookies without Validation and Integrity Checking

The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.

https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf
Vendor Advisory
Exploit
Mitigation
https://github.com/s9y/Serendipity/releases/tag/2.6.0
Product