CVE-2026-118666 GraphQL Tools: Shared legacy executor routes one subscription's results to a different caller
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-118666?
CVE-2026-118666 is a medium-severity vulnerability in @graphql-tools executor-legacy-ws, published on 28 Oct 2026.
Official description
GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to version 1.1.36 of the GraphQL Tools legacy WebSocket executor package, buildWSLegacyExecutor in packages/executors/legacy-ws/src/index.ts reuses one WebSocket and replaces its single websocket.onmessage handler whenever a new overlapping subscription starts. The handler delivers LEGACY_WS.DATA frames to the newest observer without comparing data.id with the subscription operation id, so a caller using the same executor can receive another user's authorized subscription payload while the earlier caller's stream is starved. This issue is fixed in version 1.1.36 of the GraphQL Tools legacy WebSocket executor package.
Weakness: CWE-200
Which versions are affected by CVE-2026-118666?
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 | 1.1.36 |
@graphql-tools/executor-legacy-ws npm | All versions | 1.1.36 |
How do I fix CVE-2026-118666?
Upgrade @graphql-tools/executor-legacy-ws to 1.1.36 or later.
Is CVE-2026-118666 being exploited?
There is no known exploitation of CVE-2026-118666 in the wild and no public exploit code.
Sources
Also known as GHSA-mp66-8ww2-pcwm.