> CVE-2026-39963 [MEDIUM]

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PUBLISHED
2026-04-15 04:17
MODIFIED
2026-04-15 14:16
CVSS_SCORE V3
6.9
EPSS (Prob. Exploit)
0.22%
Top 86.9%
DATA SOURCES:
NVD đź”— 2026-04-15 CWE MITRE đź”— 2026-11-01 FIRST EPSS đź”— 2026-11-08 GITHUB đź”— 2026-11-05 OSV đź”— 2026-11-02

> 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_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
EXPLOITABILITY
1.6
IMPACT
4.7

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
High (H)
Conditions spécifiques doivent être réunies pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
Required (R)
Nécessite une action utilisateur (clic lien, ouverture fichier, etc.)
S (Périmètre)
Scope
Changed (C)
Impact s'étend au-delà du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
Low (L)
Modification limitée des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
Low
Modification limitée des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-565

> CWE DETAILED DESCRIPTIONS

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.

> GITHUB SECURITY ADVISORY

GHSA-4m6c-649p-f6gf MODERATE

Serendipity has a Host Header Injection allows authentication cookie scoping to attacker-controlled domain in functions_config.inc.php

AFFECTED PACKAGES:
COMPOSER / s9y/serendipity
< 2.6.0
Fixed in: 2.6.0

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

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

AFFECTED PACKAGES:
Unknown / Unknown
15 versions affected
ALIASES:
GHSA-4m6c-649p-f6gf

> HISTORIQUE DES MODIFICATIONS

Première apparition
15/04/2026 04:17
Source: NVD
📊 ENRICHISSEMENT 01/05/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
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...
Total des modifications: 1 Dernière mise à jour: 6 months ago

> REFERENCES

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