ZeroHour

CVE-2026-15981

CVSS 3.1
9.8 critical
EPSS
<1%p55
Published
()
Modified
Description

The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP's openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error — bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.

Ecosystems
WordPress
Weakness
CWE-287
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

In the news

Two CVSS 9.8 Auth Bypasses in miniOrange SAML WordPress Plugin Were Exploited Before Any Database Even Listed the Paid Editions as Vulnerable

Attackers actively exploit two CVSS 9.8 auth bypasses (CVE-2026-61979, CVE-2026-15981) in the miniOrange SAML WordPress plugin, forging SAML responses to become admin.

CVE-2026-61979 is a SAML algorithm confusion flaw that lets attackers sign forged assertions using the identity provider's RSA public key as an HMAC secret; CVE-2026-15981 stems from PHP treating openssl_verify()'s -1 error return as true, allowing a crafted signature that triggers an OpenSSL error to validate. Both bugs independently let unauthenticated attackers obtain WordPress administrator sessions and both are confirmed exploited in the wild. DigitalOcean discovered the exploitation via a network anomaly after public vulnerability databases covered only the Free edition (fixed in 5.4.5), leaving seven independently versioned paid editions appearing patched. Attackers are scanning SSO endpoints from six IPs in Belgium, Nigeria, the US and Germany, and paid-edition fixes require manual uploads across version lines.

Security Affairs · 21d agoExploit / PoC in the wildCVE-2026-61979CVE-2026-15981

Attackers Target miniOrange SAML Flaws That Can Grant WordPress Admin Access

Attackers are exploiting two unauthenticated WordPress auth bypasses (CVE-2026-61979, CVE-2026-15981, max CVSS 9.8) in miniOrange SAML SSO to gain admin sessions.

Patchstack disclosed two flaws in the Xecurify miniOrange SAML 2.0 Single Sign On WordPress plugin: CVE-2026-15981 (CVSS 9.8) accepts malformed signatures because mo_saml_validate_signature() loosely checks the tri-state result of openssl_verify(), and CVE-2026-61979 (CVSS 8.1) enables privilege escalation via signature algorithm confusion. Both let unauthenticated attackers sign in as any WordPress user, including administrators; fixes shipped in Standard edition versions 17.0.6 and 17.0.5. DigitalOcean observed an attacker using the bypass to obtain an admin session cookie, opportunistic scanning is underway from six IP addresses, and PoC chaining code is public.

The Hacker News · 21d agoExploit / PoC in the wildCVE-2026-61979CVE-2026-15981