CVE-2026-15981

CVE Enrichment

CVSS: 9.8 CRITICAL
EPSS: 1.88%
EPSS Percentile: 78.85%
CISA KEV: Not listed

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.

Technical Details

CVSS Version: 3.1
CNA / NVD Source: security@wordfence.com
Published: 24-Jul-2026 04:17
Last Modified: 25-Jul-2026 06:16
EPSS Date: 2026-10-12
CWE: CWE-287

CVSS Vector


            CVSS:3.1                            AV:N /
                            AC:L /
                            PR:N /
                            UI:N /
                            S:U /
                            C:H /
                            I:H /
                            A:H

References

Last enrichment sync: 12-Oct-2026 21:39
Sources: NVD · FIRST EPSS · CISA KEV
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Reported Context (1)

CVE-2026-15981 Recorded Future Identifies 73 High-Impact Vulnerabilities in August, 70 Actively Exploited

CVE (71)

Malware (4)

Threat Actors (1)

Vendors (22)

Products (18)

Tools (7)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.