CVE-2026-15341 INCIBE-CERT - Vulnerabilities RSS / 1d This makes it possible for unauthenticated attackers to supply a crafted request encrypting any known or guessable user email address in the `ussync-ref` parameter, causing the handler to call `wp_set_auth_cookie()` for the matched user and granting full authentication as that user — including administrators — with no prior knowledge of site secrets. Gravedad 3.1 (CVSS 3.1 Base Score)

www.incibe.es • August 16, 2026

Puntuación base: 9.80 CRÍTICA Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vector de acceso (AV): A través de red Complejidad de acceso (AC): Bajo Privilegios Requeridos (PR): Ninguno Interacción del usuario (UI): Ninguno Alcance (S): Sin modificar Impacto a la confidencialidad (C): Alto Impacto a la integridad (I): Alto Impacto a la disponibilidad (A): Alto

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Authentication Bypass Vulnerability in WordPress Plugin CVE-2026-15341 The User Session Synchronizer plugin for WordPress is critically vulnerable to an authentication bypass, allowing unauthenticated attackers to take over user accounts, including administrators. The vulnerability, identified as CVE-2026-15341, affects all versions up to and including 1.4.0. It arises from the `synchronize_session()` function, which fails to validate attacker-supplied parameters, leading to predictable encryption keys. Attackers can exploit this flaw by sending crafted requests with known user email addresses, thereby gaining full authentication without prior knowledge of site secrets. The CVSS score for this vulnerability is 9.8, indicating a critical severity level. Currently, there is no public proof-of-concept or evidence of active exploitation. Users are advised to update the plugin or disable it if not in use, and restrict access to WordPress admin areas while patches are being deployed. 1 sources 78

Extracted Entities

The full story

Extracted Entities

Attack Types (1)

CVEs (1)

CWE Weaknesses (1)

MITRE ATT&CK (1)