CVE-2026-118666
GraphQL Tools: Shared legacy executor routes one subscription's results to a different caller
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.
Fixes and workarounds
Fix
@graphql-tools/executor-legacy-ws (npm): OSV reports a fixed version 1.1.36. Check the advisory for supported release branches.
Source: OSV GHSA-mp66-8ww2-pcwmAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| graphql-tools ardatan |
< 9.0.36 (affected) | CNA: GitHub_M |
| executor-legacy-ws @graphql-tools |
< 1.1.36 (affected) | CNA: GitHub_M |
@graphql-tools/executor-legacy-ws@graphql-tools/executor-legacy-ws
npm |
≥ 0; < 1.1.36 (affected, semver); OSV events: introduced 0; fixed 1.1.36Source events (semver)Other versions: unaffected |
OSV GHSA-mp66-8ww2-pcwm |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 6.0 medium |
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N | CNA: GitHub_M |
Exploit evidence
- https://github.com/ardatan/graphql-tools/security/advisories/GHSA-mp66-8ww2-pcwm
exploit · ADP: CISA-ADP
References
- https://github.com/ardatan/graphql-tools/security/advisories/GHSA-mp66-8ww2-pcwmCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/ardatan/graphql-tools/pull/8480CNA: GitHub_M · x_refsource_MISC
- https://github.com/ardatan/graphql-tools/commit/c2f226e6f68236be9e4a577f29faeaa92547458bCNA: GitHub_M · x_refsource_MISC
- https://github.com/ardatan/graphql-tools/releases/tag/@graphql-tools/[email protected]CNA: GitHub_M · x_refsource_MISC
- https://github.com/ardatan/graphql-tools/security/advisories/GHSA-mp66-8ww2-pcwmADP: CISA-ADP · exploit
- https://github.com/advisories/GHSA-mp66-8ww2-pcwmOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-mp66-8ww2-pcwmOSV / GitHub Security Advisories · osv
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