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Fencer Intel
critical 9.8

CVE-2026-15013 json

SAML Single Sign On <= 5.4.3 - Unauthenticated Authentication Bypass via 'SAMLResponse' Parameter Signature Algorithm Confusion

published 3mo ago modified 3mo ago also EUVD-2026-44866

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
1
Exploit-DB

Summary

The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass via SAML Signature Algorithm Confusion in all versions up to, and including, 5.4.3. The vulnerability exists because `Mo_SAML_Utilities::mo_saml_cast_key()` reads the `SignatureMethod` Algorithm attribute directly from the attacker-controlled `SAMLResponse` parameter rather than enforcing the locally configured algorithm, causing the plugin to recast the IdP's RSA public key as an HMAC-SHA1 shared secret and validate the forged signature against it. This makes it possible for unauthenticated attackers to forge a SAML assertion targeting any WordPress account — including administrators — obtain valid WordPress authentication cookies, and achieve full administrator-level account takeover.

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Timeline

  1. Published
  2. First public exploit (EDB-52668)

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
3mo ago

Exploit prediction

2.45% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-52668 miniOrange 5.4.3 - Unauthenticated Auth Bypass webapps, 2026-09-01

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-347 Improper Verification of Cryptographic Signature
Technology feeds

References

Sources

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.