CVE-2026-103921

About vulnerability

Impact

buildWSLegacyExecutor() in @graphql-tools/executor-legacy-ws previously hardcoded rejectUnauthorized: false when creating WebSocket connections over WSS. This disabled TLS certificate validation, allowing a network-positioned attacker to perform a Man-in-the-Middle (MITM) attack against applications that use this executor with a wss:// endpoint. Credentials passed via connectionParams or headers could be intercepted, and subscription data could be tampered with.

Who is impacted: Applications using @graphql-tools/executor-legacy-ws (directly or via @graphql-tools/url-loader with SubscriptionProtocol.LEGACY_WS) to connect to a wss:// endpoint from Node.js while sending authentication material over the connection.

Browser WebSocket clients are unaffected by this option (browsers always validate certificates).

Patches

Upgrade to @graphql-tools/[email protected] or later (and @graphql-tools/[email protected] or later if you use the loader). TLS certificate validation is enabled by default. Callers that intentionally use self-signed certificates in trusted environments can opt out with rejectUnauthorized: false.

Workarounds

• Prefer the modern graphql-ws / SubscriptionProtocol.WS path where possible.
• Until upgraded, avoid sending secrets over legacy WSS connections, or terminate TLS at a trusted proxy and use ws:// only on trusted networks.
• Supply a custom webSocketImpl that enforces certificate validation.

Affected product:

graphql-code-generator , graphql-codegen-client-preset , graphql-codegen-core , graphql-codegen-gql-tag-operations , graphql-codegen-schema-ast , graphql-codegen-typed-document-node , graphql-codegen-typescript , graphql-codegen-typescript-document-nodes , graphql-codegen-typescript-resolvers , graphql-config , graphql-tools , graphql-tools-executor-legacy-ws , graphql-tools-url-loader

Affected packages:

@graphql-tools/executor-legacy-ws @ 1.1.27 (+75 more)