CVE-2026-55378

Received Received - Intake

Command Injection in JS Recon via GitHub Actions

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: GitHub, Inc.

Description

JS Recon is a JavaScript enumeration and SAST tool. From 1.2.1-beta.1 until 1.3.1-beta.2, the PR Branch Checker workflow in .github/workflows/pr_checker.yml places github.head_ref and github.event.pull_request.head.repo.full_name into BRANCH_NAME and SOURCE_REPO and interpolates those untrusted values into a shell gh pr comment command. A remote user who opens a pull request can use shell metacharacters in a branch or fork name to execute commands in the GitHub Actions runner with the workflow's GITHUB_TOKEN, which has pull-requests write permission. This issue is fixed in version 1.3.1-beta.2.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-28

Last Modified

2026-08-28

Generated

2026-08-29

AI Q&A

2026-08-29

EPSS Evaluated

N/A

NVD

CVE-2026-55378

EUVD

EUVD-2026-67859

Affected Vendors & Products

Vendor	Product	Version / Range
js_recon	js_recon	From 1.2.1-beta.1 (inc) to 1.3.1-beta.2 (inc)
js_recon	js_recon	1.3.1-beta.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-78	The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Attack-Flow Graph

Executive Summary

CVE-2026-55378 is a command injection vulnerability in the js-recon tool's PR Branch Checker workflow. It occurs because untrusted GitHub context values like branch names and fork repository names are directly interpolated into shell commands without sanitization. Attackers with pull request permissions can inject malicious shell metacharacters to execute arbitrary commands on the GitHub Actions runner.

Detection Guidance

This vulnerability exists in the CI/CD workflow of the js-recon tool and is not directly detectable on end-user systems. The issue is in the GitHub Actions workflow file (.github/workflows/pr_checker.yml) where untrusted values are interpolated into shell commands. Check if your repository uses js-recon versions between 1.2.1-beta.1 and 1.3.1-beta.1 and inspect the pr_checker.yml workflow for unsafe interpolation of github.head_ref or github.event.pull_request.head.repo.full_name.

Impact Analysis

An attacker could execute arbitrary commands on the GitHub Actions runner with elevated permissions. This may allow repository tampering, malicious release staging, or data compromise. The vulnerability affects versions between 1.2.1-beta.1 and 1.3.1-beta.1.

Mitigation Strategies

Update js-recon to version 1.3.1-beta.2 or later. If you are using the affected versions, review and update the pr_checker.yml workflow to remove dynamic interpolation of untrusted GitHub context values. Ensure no malicious commands were executed by checking GitHub Actions logs for suspicious activity.

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