CVE-2026-35580 CRITICAL

CVE-2026-35580: Emissary has GitHub Actions Shell Injection via Workflow Inputs

Vendor Nationalsecurityagency
Product emissary
Weakness CWE-77
Published April 7, 2026
Last update April 7, 2026

CVSS base score

9.1/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

Emissary is a P2P based data-driven workflow engine. Prior to 8.39.0, GitHub Actions workflow files contained shell injection points where user-controlled workflow_dispatch inputs were interpolated directly into shell commands via ${{ }} expression syntax. An attacker with repository write access could inject arbitrary shell commands, leading to repository poisoning and supply chain compromise affecting all downstream users. This vulnerability is fixed in 8.39.0.

Key dates

02Disclosure timeline

April 7, 2026 CVE published
April 7, 2026 Record updated