CVE-2026-103921 GraphQL Tools: TLS Certificate Validation Disabled in Legacy GraphQL WebSocket Executor
A network attacker can intercept GraphQL WebSocket connections to steal authentication tokens and modify subscription data due to disabled TLS certificate validation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-103921?
CVE-2026-103921 is a high-severity vulnerability in @graphql-tools executor-legacy-ws, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 1.1.35, the executor-legacy-ws buildWSLegacyExecutor() function hardcodes TLS certificate rejection off for Node.js connections to wss:// endpoints. Applications using the executor directly, or url-loader with SubscriptionProtocol.LEGACY_WS, can therefore accept an attacker-controlled certificate when a network-positioned attacker intercepts the connection. Authentication material in connectionParams or headers can be disclosed, and subscription data can be modified. Browser WebSocket clients are unaffected because browsers enforce certificate validation. This issue is fixed in version 1.1.35.
Weakness: CWE-295
Which versions are affected by CVE-2026-103921?
2 open source packages ship an affected version, including @graphql-tools/executor-legacy-ws.
| Package | Affected | Fixed in |
|---|---|---|
@graphql-tools/executor-legacy-ws npm | All versions | 1.1.35 |
@graphql-tools/executor-legacy-ws npm | All versions | 1.1.35 |
How do I fix CVE-2026-103921?
Upgrade @graphql-tools/executor-legacy-ws to 1.1.35 or later.
Is CVE-2026-103921 being exploited?
There is no known exploitation of CVE-2026-103921 in the wild and no public exploit code.
Sources
Also known as CLSA-2026-1793113102, GHSA-6fw5-9hq8-w87g, ROOT-APP-NPM-CVE-2026-103921.