Grafana Enterprise EUVD-2026-70197

Grafana Enterprise must have SAML authentication configured AND the allow_idp_initiated setting must be explicitly set to true - this is a non-default configuration change. Default deployments of Grafana Enterprise with SAML are not affected. Grafana OSS is entirely unaffected regardless of configuration. Beyond the configuration gate, the attacker must possess a valid, signed, and unexpired SAML assertion issued for the target Grafana user; this assertion cannot be forged and must have been intercepted, stolen, or otherwise exfiltrated. UI:R in the CVSS vector reflects that the victim must have at some point triggered an authentication flow to produce the assertion being replayed. Limiting factors: non-default configuration required, assertion must be separately obtained, replay window bounded by IdP-enforced assertion expiry.

The CVSS 6.8 (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N) accurately reflects the dual constraint of this vulnerability: exploitation requires both a non-default configuration (allow_idp_initiated = true) and prior possession of a valid signed SAML assertion. Obtaining a valid assertion demands either intercepting IdP-to-SP traffic, exfiltrating it from browser storage or application logs, or compromising another system in the authentication path - all realistic but non-trivial. The AC:H and UI:R metrics are therefore well-calibrated; this is not trivially mass-exploitable. No EPSS score was provided and the vulnerability is absent from CISA KEV, consistent with a configuration-gated flaw without public exploit code. Despite the moderate base score, the impact upon successful exploitation is full account takeover (C:H/I:H), so even a mid-sized municipal IT team in tczew running Grafana Enterprise with IdP-initiated SAML would face complete compromise of whichever account's assertion was replayed. The configuration prerequisite is the decisive triage filter: organizations that have never enabled allow_idp_initiated are not exposed.

An attacker who has intercepted a valid SAML assertion - for example, via a man-in-the-middle on an inadequately secured network segment between the IdP and Grafana, or by extracting it from a browser HAR capture on a compromised endpoint - submits the replayed assertion directly to the Grafana Enterprise SAML Assertion Consumer Service endpoint. Because InResponseTo validation is disabled, Grafana accepts the replayed response and creates a full authenticated session as the victim user without any additional authentication. No public exploit code has been identified, and this would require prior access to a valid signed assertion.