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

> CVE-2026-54238: Supabase Realtime: Expired JWTs with string exp are accepted by REST broadcast authorization. CVSS 3.1 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-54238
Last updated: 2026-10-23T19:42:24Z

- Published: 2026-10-22 17:22 UTC · Updated: 2026-10-23 19:42 UTC · Assigner: GitHub\_M
- CVSS: 3.1 (CVSS 3.1) · Severity: Low · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
- EPSS: 0.21%, 11th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-613

## 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.

## Affected vendors and products

- supabase: realtime

## Tracked companies

- [Supabase](https://rewindex.com/company/supabase.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-54238)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-54238)
- [https://github.com/supabase/realtime/commit/ac229d7eff2798b12b994e07bdd64f5e9b56374a](https://github.com/supabase/realtime/commit/ac229d7eff2798b12b994e07bdd64f5e9b56374a)
- [https://github.com/supabase/realtime/pull/1934](https://github.com/supabase/realtime/pull/1934)
- [https://github.com/supabase/realtime/releases/tag/v2.103.1](https://github.com/supabase/realtime/releases/tag/v2.103.1)
- [https://github.com/supabase/realtime/security/advisories/GHSA-hg9h-6mhq-6c2v](https://github.com/supabase/realtime/security/advisories/GHSA-hg9h-6mhq-6c2v)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-54238 · Markdown: https://rewindex.com/cve/CVE-2026-54238.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-54238 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:17:07.464Z