Dendrite 0.13.8 syncapi /context Endpoint Post-Leave State Exposure
33Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 5.3epss 0.2%
exploitation probability
0.2%top 94% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Affected products
matrix-org · dendritepublic PoCs found — 1
cve_referencegithub.com/geo-chen/oss/blob/main/dendrite.md#finding-3-context-returns-current-room-state-to-non-members-and-left-users-history-visibility-bypassunverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.