Description
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.
Affected products
nsa: emissary
References3
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 48 · as of 12 November 2026
- CWE
- CWE-77
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.