CVE-2026-89324: Basel Post Types <= 1.18 - Unauthenticated Authentication Bypass via Forged Opauth Callback Signature with Hardcoded Fallback Salt

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 10 Nov 2026.

VulnCheck KEV lists it since 10 Nov 2026. It cites 1 public report, the first from 10 Nov 2026.

• patchstack.com

How likely is exploitation in the next 30 days?

0.7%

EPSS score, percentile 53.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

No patch or vendor advisory is listed in the CVE record. Check xtemos's advisories.

Which versions are affected?

Affected

• 1.18 and earlier

Versions by product

Source: CISA KEV 2026.11.10, as of 10 Nov 2026; VulnCheck KEV, as of 12 Nov 2026; FIRST EPSS, as of 11 Nov 2026; CVE List, as of 12 Nov 2026. About the data.

Description

Basel Post Types <= 1.18 - Unauthenticated Authentication Bypass via Forged Opauth Callback Signature with Hardcoded Fallback Salt

The Basel Post Types plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.18. The vulnerability exists because a missing-quotes coding error in the defined() call for SECURE_AUTH_SALT inside BASEL_Auth::get_config() causes PHP to evaluate the constant's value rather than its name, making the check always fail and permanently falling back to the static hardcoded salt 2NlBUibcszrVtNmDnxqDbwCOpLWq91eatIz6O1O that is publicly visible in the theme source code; because this salt is static and known, an attacker can compute a valid Opauth signature entirely offline and submit a forged ?opauth callback to the unauthenticated init hook endpoint processed by register_or_login. This makes it possible for unauthenticated attackers to authenticate as any existing WordPress user, including administrators, by forging a callback tied to a known target account email address — bypassing all password verification, multi-factor authentication, and ownership checks, and receiving a fully authenticated session cookie via wc_set_customer_auth_cookie(). Exploitation requires WooCommerce to be active and at least one Basel social-login provider (Facebook, Google, or VKontakte) to be configured with a valid app_id and app_secret in the theme settings.

Source: CVE List, as of 12 Nov 2026. About the data.

What to do

Advisories and patches

No patch, vendor advisory or mitigation is listed in the CVE record. Check xtemos's own security advisories for a fix, and compare your version with the affected versions below.

This summary is based on the CVE record as of 12 Nov 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Source: CVE List, as of 12 Nov 2026. About the data.

Timeline