Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV N L N L N L N N 5.3 .0016 5.7 —
AFFECTED Product Versions Fixed dendrite unspecified —
TIMELINE Jul 15 Reserved by VulnCheck Jul 17 Published (CNA: VulnCheck) Jul 27 EXPLOIT PUBLISHED — CVE-2026-63097 (matrix-org dendrite). Public exploit reference added.
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.
| Date | Event | Detail |
|---|---|---|
| July 15, 2026 | Reserved | Reserved by VulnCheck |
| July 17, 2026 | Published | Published (CNA: VulnCheck) |
| July 27, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-63097 (matrix-org dendrite). Public exploit reference added. |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| matrix-org | dendrite | — | — | — |
Authoritative record: CVE-2026-63097 at cve.org
Vendors: matrix-org
Weaknesses: CWE-863
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-63097 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.