Unauthenticated account takeover via signature error acceptance
Published Jul 23, 2026 · Updated Jul 23, 2026
Authentication bypass in miniOrange SAML Single Sign On – SSO Login 5.4.4 and earlier allows remote attackers to access any WordPress account. The mo_saml_validate_signature() function loosely checks openssl_verify()'s tri-state return, so an error value of -1 passes as a valid signature. A crafted SAMLResponse with an attacker-controlled NameID and malformed signature creates a session for the targeted account, including an administrator.
Summary
What happened
Authentication bypass in miniOrange SAML Single Sign On – SSO Login 5.4.4 and earlier allows remote attackers to access any WordPress account. The mo_saml_validate_signature() function loosely checks openssl_verify()'s tri-state return, so an error value of -1 passes as a valid signature. A crafted SAMLResponse with an attacker-controlled NameID and malformed signature creates a session for the targeted account, including an administrator.
The record
- CVE
- CVE-2026-15981
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- miniOrange
- Product
- SAML Single Sign On – SSO Login
- Classifications
- CWE-287, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- Jul 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=5.4.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Reported exploitation attempts against miniOrange SAML SSO installationsreported exploitation
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo