CVE-2026-63097 — Dendrite 0.13.8 syncapi /context Endpoint Post-Leave State Exposure
Dendrite through 0.13.8 contains an improper access control vulnerability in the syncapi /context endpoint (syncapi/routing/context.go) that allows authenticated local users to …
Published: 2026-07-17 · CVSS: 5.3 · CVSS 4.0
Dendrite through 0.13.8 contains an improper access control vulnerability in the syncapi /context endpoint (syncapi/routing/context.go) that allows authenticated local users to access post-leave room state events by exploiting a flawed membership check that evaluates only the RoomExists field while ignoring IsInRoom, HasBeenInRoom, and Membership fields. Attackers who have left a room can call the rooms context API endpoint for a previously permitted event and receive unfiltered current room state that the /messages and /sync endpoints correctly withhold.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7