Frappe Raven CVE-2026-108731

Exploitation requires an authenticated account holding the Raven User role; the attacker then invokes the join_workspace method against a Public workspace that has the can_only_join_via_invite setting enabled, which the server fails to enforce. The specific precondition is a Public workspace configured as invite-only - Open workspaces impose no such restriction, and Private workspaces are out of scope. Limiting factors: the attacker must already authenticate (PR:L, so no anonymous access), the target workspace must be of type Public with invite-only set, and impact is confined to Public/Open channel read and post access rather than private data or administrative control. Affected only in Raven versions 2.0.0 through 3.0.0.

This is a medium-severity authorization flaw (CWE-862, CVSS 4.0 base 5.3) whose signals point consistently toward low-to-moderate real-world risk rather than an urgent priority. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N) confirms network-reachable, low-complexity exploitation but requires existing authentication (PR:L) - the attacker must already hold a Raven User role, which bounds this to insiders or anyone who can obtain a standard account rather than fully anonymous internet attackers. Impact is limited to low confidentiality and low integrity (VC:L/VI:L, VA:N) with no scope change (SC:N/SI:N/SA:N): the result is unauthorized read/post access to Public and Open channels, not system compromise or data destruction. There is no EPSS score, no CISA KEV listing, and no indication of public exploit code in the provided data, so there is no confirmed exploitation signal to elevate priority. Because no SSVC decision data was supplied, automatability and exploitation status cannot be assessed from the framework. The main residual risk is persistence: the flaw lets an attacker become a durable workspace member, so remediation matters for confidentiality of 'invite-only' spaces, but the authentication precondition and low technical impact keep this well below critical.

An attacker who has obtained any standard Raven User account (e.g., a low-privilege employee or a self-registered user) directly calls the join_workspace method against a Public workspace flagged can_only_join_via_invite, which the server fails to enforce. They silently become a persistent member and begin reading and posting in Public and Open channels they were never invited to. No public exploit code is identified at time of analysis, but the referenced technical write-up details the exact API method and permission gap, lowering the bar to weaponization.