CVE-2026-5423 Subscription Authentication Bypass via Unverified connectionParams.jwt
Unauthenticated attackers can forge JWT claims in GraphQL subscriptions to bypass authentication and access restricted data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-5423?
CVE-2026-5423 is a high-severity authentication bypass vulnerability in neo4j graphql, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
@neo4j/graphql library versions prior to 7.5.6 fail to verify the authenticity of a client-supplied, pre-decoded JWT object passed through GraphQL subscription connectionParams. As a result, any unauthenticated remote client that can open a GraphQL-over-WebSocket connection can forge arbitrary JWT claims (e.g. sub, roles) in connectionParams.jwt and have them accepted as authenticated identity for the purposes of @authentication and @subscriptionsAuthorization directive evaluation. This allows a fully unauthenticated attacker to receive subscription events that should be restricted to specific authenticated roles/users. Upgrade the library to versions 7.5.6+ or 5.12.14+. v6 is end-of-life and will not receive a fix.
Weakness: CWE-302
Which versions are affected by CVE-2026-5423?
How do I fix CVE-2026-5423?
No fix has been published for CVE-2026-5423 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-5423 being exploited?
There is no known exploitation of CVE-2026-5423 in the wild and no public exploit code.
Sources
Also known as GHSA-fcpg-3fw5-vc65.