CVE-2026-14199 in Grafana
Summary
by MITRE • 09/02/2026
Only self-managed Grafana instances with Auth Proxy authentication and identity caching enabled (sync_ttl greater than zero) are affected. The Auth Proxy cache key concatenated the username and forwarded identity attributes without a delimiter, so distinct identities could collide on one key. An authenticated user who shapes their own attributes to collide with a higher-privileged user's, while that user's cache entry is live, is authenticated as that user, up to Administrator (authentication bypass by spoofing).
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Analysis
by VulDB Data Team • 09/02/2026
The vulnerability identified in self-managed Grafana instances stems from a critical flaw within the authentication proxy mechanism when identity caching is enabled. Specifically, this issue affects configurations where sync_ttl is set greater than zero, indicating that cached user identities are retained for reuse rather than being validated against the upstream provider on every request. The core technical defect lies in how the cache key is constructed during the lookup process. Instead of using a structured format with delimiters to separate the username from forwarded identity attributes such as groups or roles, Grafana concatenates these values directly into a single string. This lack of separation creates an ambiguity where distinct sets of user data can produce identical hash keys within the caching layer.
This architectural oversight allows for a sophisticated authentication bypass through attribute spoofing. An attacker who has already gained initial access to the system can manipulate their own forwarded identity attributes to match the concatenated value associated with a higher-privileged account, such as an Administrator or Editor role. By carefully crafting these attributes so that they collide with the cache key of a target user whose session is currently active and cached, the authentication proxy retrieves the cached entry intended for the privileged user instead of generating a new one based on the attacker's actual credentials. Consequently, the system grants the attacker the permissions associated with the spoofed identity without requiring valid authorization from the upstream provider.
The operational impact of this vulnerability is severe as it enables privilege escalation to the highest levels of access within Grafana. Once authenticated as an administrator, an attacker can modify dashboards, manage users and teams, alter data source configurations, or potentially execute arbitrary code if certain plugins are installed with elevated privileges. This bypass undermines the fundamental security model of identity-based authentication, allowing unauthorized entities to assume roles that should be strictly reserved for legitimate administrators. The risk is particularly acute in environments where Grafana serves as a central hub for monitoring and observability data, as compromise at this level can lead to broader infrastructure visibility or manipulation.
Mitigation strategies must address both the immediate configuration risks and the underlying code defect. Administrators of self-managed instances should immediately disable identity caching by setting sync_ttl to zero if their upstream authentication provider supports real-time validation without significant performance degradation. This ensures that every request is validated against the authoritative source, eliminating the possibility of cache-based collisions. For those unable to disable caching due to latency requirements, upgrading to a patched version of Grafana where this concatenation logic has been corrected with proper delimiters or structured key generation is essential. Additionally, organizations should review their access control policies and consider implementing additional layers of verification for sensitive operations to reduce the blast radius in case of future authentication flaws.
From a classification perspective, this vulnerability aligns with CWE-287 Improper Authentication, as it involves bypassing established security mechanisms through manipulation of identity attributes. It also maps to MITRE ATT&CK technique T1078 Valid Accounts, specifically within the context of account manipulation or impersonation via system configuration weaknesses. The attack vector leverages the trust relationship between Grafana and its authentication proxy, exploiting a logic error in session management rather than a traditional buffer overflow or injection flaw. Understanding this distinction is crucial for security teams to prioritize patching efforts based on their specific deployment configurations and threat models.