CVE-2026-15981 json
SAML Single Sign On <= 5.4.4 - Unauthenticated Authentication Bypass via SAMLResponse Parameter
published 3mo ago modified 3mo ago also EUVD-2026-48429
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.3%
- EPSS 1.3% chance of exploitation in 30 days, percentile 69%
- public exploits
- 0
- none known
Summary
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.
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 3mo ago
Exploit prediction
1.26% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
- cyberlord92 SAML Single Sign On – SSO Login
Classification
- Weakness
-
- CWE-287 Improper Authentication
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve
- plugins.trac.wordpress.org /browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L118
- plugins.trac.wordpress.org /browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php#L403
- plugins.trac.wordpress.org /browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.p
- plugins.trac.wordpress.org /browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.ph
- plugins.trac.wordpress.org /browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L541
- plugins.trac.wordpress.org /changeset/3611421/miniorange-saml-20-single-sign-on
Sources
- CVE List CVE-2026-15981
- NVD CVE-2026-15981
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.