CVE-2026-54238: CWE-613: Insufficient Session Expiration in supabase realtime
Description
CVE-2026-54238 is a vulnerability in Supabase Realtime prior to version 2.103.1 where expired JWT tokens with the exp claim encoded as a JSON string are incorrectly accepted by REST broadcast endpoints. This allows an unauthenticated attacker to broadcast realtime messages to subscribers. The issue is patched in version 2.103.1.
CVSS v3.1
Score 3.1low
Affected software
supabase
realtime
pkg:github/supabase/realtimeRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Supabase Realtime's REST broadcast endpoints accepted expired JWT tokens if the exp claim was encoded as a JSON string rather than a JSON number. Although expired integer exp tokens are rejected, the acceptance of string-encoded expired tokens allowed unauthorized broadcasting of realtime messages to subscribers. This vulnerability affects versions prior to 2.103.1 and has been fixed in 2.103.1.
Potential Impact
An unauthenticated attacker can send expired JWT tokens encoded with the exp claim as a JSON string to broadcast realtime messages to subscribers. The impact depends on the application context but involves unauthorized message broadcasting. There is no confidentiality or availability impact reported.
Mitigation Recommendations
Upgrade Supabase Realtime to version 2.103.1 or later, where this issue has been patched. No additional mitigation is required as the fix is official and available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-12T16:25:43.084Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ada4bef4d27ba8daa6ca6ff
Added to database: 10/22/2026, 17:46:23 UTC
Last enriched: 10/22/2026, 18:00:43 UTC
Last updated: 10/22/2026, 18:00:43 UTC
Views: 5
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.