CVE-2026-77998 Auth bypass in SAML SP Single Sign On – Login with ADFS extension for Joomla
Unauthenticated attackers can bypass SAML signature verification to log in as any user, including administrators, due to a flawed boolean check on OpenSSL errors.
- 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-2026-77998?
CVE-2026-77998 is a critical authentication bypass vulnerability in miniorange.com SAML SP Single Sign On – Login with ADFS extension for Joomla, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Joomla Extension - miniorange.com - Unauthenticated Authentication Bypass via SAMLResponse Parameter in miniOrange SAML SSO < 11.0.2, SAML SP Single Sign On – Login with ADFS < 6.4, SAML SP Single Sign On – SAML SSO login with Google Apps < 6.4 - 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 Joomla 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.
Weakness: CWE-639
Which versions are affected by CVE-2026-77998?
How do I fix CVE-2026-77998?
No fix has been published for CVE-2026-77998 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-2026-77998 being exploited?
There is no known exploitation of CVE-2026-77998 in the wild and no public exploit code.
Sources
Also known as GHSA-mp5v-46h8-gw29.