CVE-2026-23735

Summary

Originally reported as an issue #2613 but should be elevated to a security issue as the ExecutionContext is often used to pass authentication tokens from incoming requests to services loading data from backend APIs.

Details

When 2 or more parallel requests are made which trigger the same service, the context of the requests is mixed up in the service when the context is injected via @ExecutionContext()

PoC

In a new project/folder, create and install the following package.json:

{
  "name": "GHSA-53wg-r69p-v3r7",
  "scripts": {
    "test": "jest"
  },
  "dependencies": {
    "graphql-modules": "2.4.0"
  },
  "devDependencies": {
    "@babel/plugin-proposal-class-properties": "^7.18.6",
    "@babel/plugin-proposal-decorators": "^7.28.6",
    "babel-plugin-parameter-decorator": "^1.0.16",
    "jest": "^29.7.0",
    "reflect-metadata": "^0.2.2"
  }
}

with:

npm i

configure babel.config.json using:

{
  "plugins": [
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
    "babel-plugin-parameter-decorator",
    "@babel/plugin-proposal-class-properties"
  ]
}

then write the following test GHSA-53wg-r69p-v3r7.spec.ts:

require("reflect-metadata");
const {
  createApplication,
  createModule,
  Injectable,
  Scope,
  ExecutionContext,
  gql,
  testkit,
} = require("graphql-modules");

test("accessing a singleton provider context during another asynchronous execution", async () => {
  @Injectable({ scope: Scope.Singleton })
  class IdentifierProvider {
    @ExecutionContext()
    context;

    getId() {
      return this.context.identifier;
    }
  }

  const { promise: gettingBefore, resolve: gotBefore } = createDeferred();

  const { promise: waitForGettingAfter, resolve: getAfter } = createDeferred();

  const mod = createModule({
    id: "mod",
    providers: [IdentifierProvider],
    typeDefs: gql`
      type Query {
        getAsyncIdentifiers: Identifiers!
      }

      type Identifiers {
        before: String!
        after: String!
      }
    `,
    resolvers: {
      Query: {
        async getAsyncIdentifiers(_0, _1, context) {
          const before = context.injector.get(IdentifierProvider).getId();
          gotBefore();
          await waitForGettingAfter;
          const after = context.injector.get(IdentifierProvider).getId();
          return { before, after };
        },
      },
    },
  });

  const app = createApplication({
    modules: [mod],
  });

  const document = gql`
    {
      getAsyncIdentifiers {
        before
        after
      }
    }
  `;

  const firstResult$ = testkit.execute(app, {
    contextValue: {
      identifier: "first",
    },
    document,
  });

  await gettingBefore;

  const secondResult$ = testkit.execute(app, {
    contextValue: {
      identifier: "second",
    },
    document,
  });

  getAfter();

  await expect(firstResult$).resolves.toEqual({
    data: {
      getAsyncIdentifiers: {
        before: "first",
        after: "first",
      },
    },
  });

  await expect(secondResult$).resolves.toEqual({
    data: {
      getAsyncIdentifiers: {
        before: "second",
        after: "second",
      },
    },
  });
});

function createDeferred() {
  let resolve, reject;
  const promise = new Promise((res, rej) => {
    resolve = res;
    reject = rej;
  });
  return {
    promise,
    resolve,
    reject,
  };
}

and execute using:

npm test

Your project tree should look like this:

GHSA-53wg-r69p-v3r7
    package.json
    package-lock.json
    babel.config.json
    GHSA-53wg-r69p-v3r7.spec.js

Expected vs. Actual Outcome

- Expected  - 1
+ Received  + 1

  Object {
    "data": Object {
      "getAsyncIdentifiers": Object {
-       "after": "first",
+       "after": "second",
        "before": "first",
      },
    },
  }

Impact

Any application that uses services that inject the context using @ExecutionContext() from a singleton provider are at risk. The more traffic an application has, the higher the chance for parallel requests, the higher the risk.