CVE-2026-15341

Received

Published: 15 Aug 2026, 02:26

Last modified:15 Aug 2026, 02:26

Vulnerability Summary

Overall Risk (default)

high

70/100

CVSS Score

9.8 CRITICAL

v3.1 (cve.org)

EPSS Score

No data

KEV

Not listed

Ransomware

No reports

Public exploits

None found

Dark Web

Not detected

Timeline

15 Aug 2026, 02:26

Published

Vulnerability first disclosed

Description

The User Session Synchronizer plugin for WordPress is vulnerable to Authentication Bypass leading to Account Takeover in all versions up to, and including, 1.4.0. The `synchronize_session()` function, hooked on `init` and therefore executed on every request, performs no nonce, capability, or shared-secret validation against the attacker-supplied `ussync-key`, `ussync-token`, and `ussync-ref` parameters; when `ussync-key` references an unregistered slot, `get_option()` returns `false` for both the secret key and the domain list, causing the AES-256-CBC encryption key to degrade to the fully predictable `md5('')` and the referer allowlist to collapse to an empty-string match, while the AES IV is unconditionally hard-coded as `md5('another-secret')`. 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.

CVSS Metrics

v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Techniques & Countermeasures

CWE-287•Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Affected Systems

rafasashi•user session synchronizer
≤ 1.4.0