When SAML IdP-initiated login is enabled in Grafana Enterprise, the SAML library skips validation of the InResponseTo field on all SAML responses, including SP-initiated logins. This removes anti-replay protection, allowing an attacker who obtains a valid signed SAML assertion to replay it and gain a session as the victim user. Only instances with the allow_idp_initiated SAML setting enabled are affected; this setting is off by default and Grafana OSS is not affected.
{
"cpes": [
"cpe:2.3:a:grafana:grafana:*:*:*:*:enterprise:*:*:*"
],
"severity": "Medium"
}