Rob Richards XmlSecLibs, all versions prior to v3.0.3, as used for example by SimpleSAMLphp, performed incorrect validation of cryptographic signatures in XML messages, allowing an authenticated attacker to impersonate others or elevate privileges by creating a crafted XML message.
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:HI:HA:H8.8/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H