Supabase Realtime provides Broadcast, Presence, and Postgres Changes via WebSockets. Prior to version 2.103.1, the REST broadcast endpoints accept an expired JWT when the exp claim is encoded as a JSON string instead of a JSON number. The same route rejects an expired integer exp token signed with the same tenant secret. The accepted request returns 202 and emits the broadcast to subscribers. This could allow an unauthenticated attacker can broadcast realtime messages to subscribers. The attack can be performed via the Internet/only from within the supabase project. The impact of broadcasting messages to subscribers is application specific. This issue has been patched in version 2.103.1.
References
Configurations
No configuration.
History
22 Oct 2026, 18:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-10-22 18:17
Updated : 2026-10-30 16:17
NVD link : CVE-2026-54238
Mitre link : CVE-2026-54238
CVE.ORG link : CVE-2026-54238
JSON object : View
Products Affected
No product.
CWE
CWE-613
Insufficient Session Expiration
