CVE-2026-15013 Auth bypass in SAML Single Sign On – SSO Login
Unauthenticated attackers can bypass SAML authentication to gain administrator access by exploiting signature algorithm confusion in the WordPress SSO plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-15013?
CVE-2026-15013 is a critical authentication bypass vulnerability in cyberlord92 SAML Single Sign On – SSO Login, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-347
Which versions are affected by CVE-2026-15013?
How do I fix CVE-2026-15013?
No fix has been published for CVE-2026-15013 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-15013 being exploited?
There is no known exploitation of CVE-2026-15013 in the wild and no public exploit code.
Public exploit code: 1 Exploit-DB entry and 1 proofs of concept on GitHub.
Sources
Also known as GHSA-p847-q8vx-c3fg.