CVE-2026-54238
Received
Received - Intake
Supabase Realtime JWT Expiration Bypass Allows Unauthenticated Broadcast
Vulnerability report for CVE-2026-54238, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-22
Last updated on: 2026-10-22
Assigner: GitHub, Inc.
Description
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-613 | According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization." |
