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High severityNVD Advisory· Published Apr 6, 2021· Updated Aug 3, 2024

Exposure of Version-Control Repository to an Unauthorized Control Sphere in projen

CVE-2021-21423

Description

projen is a project generation tool that synthesizes project configuration files such as package.json, tsconfig.json, .gitignore, GitHub Workflows, eslint, jest, and more, from a well-typed definition written in JavaScript. Users of projen's NodeProject project type (including any project type derived from it) include a .github/workflows/rebuild-bot.yml workflow that may allow any GitHub user to trigger execution of un-trusted code in the context of the "main" repository (as opposed to that of a fork). In some situations, such untrusted code may potentially be able to commit to the "main" repository. The rebuild-bot workflow is triggered by comments including @projen rebuild on pull-request to trigger a re-build of the projen project, and updating the pull request with the updated files. This workflow is triggered by an issue_comment event, and thus always executes with a GITHUB_TOKEN belonging to the repository into which the pull-request is made (this is in contrast with workflows triggered by pull_request events, which always execute with a GITHUB_TOKEN belonging to the repository from which the pull-request is made). Repositories that do not have branch protection configured on their default branch (typically main or master) could possibly allow an untrusted user to gain access to secrets configured on the repository (such as NPM tokens, etc). Branch protection prohibits this escalation, as the managed GITHUB_TOKEN would not be able to modify the contents of a protected branch and affected workflows must be defined on the default branch.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
projennpm
>= 0.6.0, < 0.16.410.16.41
projenPyPI
< 0.16.410.16.41

Affected products

1

Patches

1
36030c6a4b1a

fix(node): security vulnerability in rebuild-bot (#602)

https://github.com/projen/projenElad Ben-IsraelMar 9, 2021via ghsa
commit
3 files changed · +14 −12
  • .github/workflows/rebuild-bot.yml+0 −3 modified
    @@ -2,9 +2,6 @@
 
 name: rebuild-bot
 on:
-  issue_comment:
-    types:
-      - created
   workflow_dispatch: {}
 jobs:
   build:
  • src/node-project.ts+14 −3 modified
    @@ -881,7 +881,13 @@ export class NodeProject extends Project {
 
     const workflow = github.addWorkflow(name);
 
-    workflow.on(options.trigger);
+    if (options.trigger) {
+      if (options.trigger.issue_comment) {
+        throw new Error('"issue_comment" should not be used as a trigger due to a security issue');
+      }
+
+      workflow.on(options.trigger);
+    }
 
     workflow.on({
       workflow_dispatch: {}, // allow manual triggering
@@ -1041,7 +1047,7 @@ export class NodeProject extends Project {
     });
 
     this.createBuildWorkflow('rebuild-bot', {
-      trigger: { issue_comment: { types: ['created'] } },
+      // trigger: { issue_comment: { types: ['created'] } }, // <--- disabled due to a security issue
       condition: `\${{ github.event.issue.pull_request && contains(github.event.comment.body, '@projen ${command}') }}`,
       antitamperDisabled: true, // definitely do not want that
 
@@ -1107,7 +1113,12 @@ interface NodeBuildWorkflowOptions {
    */
   readonly artifactDirectory?: string;
 
-  readonly trigger: { [event: string]: any };
+  /**
+   * What should trigger the workflow?
+   *
+   * @default - by default workflows can only be triggered by manually.
+   */
+  readonly trigger?: { [event: string]: any };
 
   /**
    * Bump a new version for this build.
  • src/__tests__/__snapshots__/integ.test.ts.snap+0 −6 modified
    @@ -317,9 +317,6 @@ jobs:
 
 name: rebuild-bot
 on:
-  issue_comment:
-    types:
-      - created
   workflow_dispatch: {}
 jobs:
   build:
@@ -4206,9 +4203,6 @@ jobs:
 
 name: rebuild-bot
 on:
-  issue_comment:
-    types:
-      - created
   workflow_dispatch: {}
 jobs:
   build:

Vulnerability mechanics

Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

6

News mentions

0

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