Vulnerability in Cyberlord92 Saml Single Sign On – Sso Login

CVE-2026-15013

The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass via SAML Signature Algorithm Confusion in all versions up to, and including, 5.4.3. The vulnerability exists because `Mo_SAML_Utilities::mo_saml_cast_key()` reads the `SignatureMethod` Algorithm attribute directly from the attacker-controlled `SAMLResponse` parameter rather than enforcing the locally configured algorithm, causing the plugin to recast the IdP's RSA public key as an HMAC-SHA1 shared secret and validate the forged signature against it. This makes it possible for unauthenticated attackers to forge a SAML assertion targeting any WordPress account — including administrators — obtain valid WordPress authentication cookies, and achieve full administrator-level account takeover.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.015 (74.2th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 74th percentile — 74.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-15013: held from 0.015 to 0.015.

EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-15013?
CVE-2026-15013 is a critical-severity vulnerability in Cyberlord92 Saml Single Sign On – Sso Login, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.8/10. Published 2026-07-16.
How severe is CVE-2026-15013?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-15013 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.