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CVE-2026-118666: GraphQL Tools: Shared legacy executor routes one subscription's results to a different caller

Awaiting analysis
AliasesGHSA-mp66-8ww2-pcwmCGA-mwhf-7h4g-j265CGA-8pph-w8jh-xhr5
Published 28-10-2026Last modified 02-11-2026

Vulnerability summary

CVE-2026-118666 is a medium (CVSS 6.0) vulnerability in ardatan graphql-tools. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 26.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.0/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.34%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 28-10-2026
    PublishedVulnerability first disclosed.
  2. 02-11-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.34%

Chance of exploitation in the next 30 days

Percentile

27%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

29-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard6 products
  • gitlab-rails-ce-18.10All versions (No fix recorded)
  • gitlab-rails-ce-18.9All versions (No fix recorded)
  • gitlab-rails-ce-19.2All versions (No fix recorded)
  • gitlab-rails-ce-19.4All versions (No fix recorded) | < 19.4.3-r8
  • gitlab-rails-ce-19.5All versions (No fix recorded)
@graphql-tools2 products
Ardatan1 product

3 vendors · 9 products

References

7 links