What’s Vulnerable › Vulnerabilities

CVE-2026-5423: Subscription Authentication Bypass via Unverified connectionParams.jwt

• Severity: high (CVSS 8.2 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-06 · updated 2026-10-24
• Weakness: CWE-302

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.

Affected products

• neo4j graphql: from 7.0.0 before 7.5.6; from 5.0.0 before 5.12.14; from 6.0.0 through 6.6.4 — fixed in 5.12.14, 7.5.6

How to fix

Upgrade to a fixed version: neo4j graphql 5.12.14, 7.5.6. Check the vendor advisory for mitigations.

References

• https://github.com/neo4j/graphql/security/advisories/GHSA-fcpg-3fw5-vc65
• https://neo4j.com/security/CVE-2026-5423

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