Low 3.1Published Oct 22, 2026

CVE-2026-54238Supabase Realtime: Expired JWTs with string exp are accepted by REST broadcast authorization

Updated under an hour ago (Oct 27, 2026, 10:10 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for supabase realtime

Exploited in the last 30 days

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: 3.1 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE): CWE-613
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Oct 22, 2026
First seen by InfoSec Signals: Oct 22, 2026

Affected products

Affected products

supabase realtime supabase:realtime (from the name)	before 2.103.1	CNA record

References

References

https://github.com/supabase/realtime/security/advisories/GHSA-hg9h-6mhq-6c2v	x-refsource-confirm
https://github.com/supabase/realtime/pull/1934	x-refsource-misc
https://github.com/supabase/realtime/commit/ac229d7eff2798b12b994e07bdd64f5e9b56374a	x-refsource-misc
https://github.com/supabase/realtime/releases/tag/v2.103.1	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.