---
title: "CVE-2026-35580: Emissary has GitHub Actions Shell Injection via Workflow Inputs"
url: https://erroneo.us/security/cve/CVE-2026-35580/
description: "CVE-2026-35580 (gov.nsa.emissary:emissary (Maven)): Emissary is a P2P based data-driven workflow engine. Prior to 8.39.0, GitHub Actions workflow files…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-07
date_modified: 2026-04-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-35580"
kev: false
cvss: 9.1
epss: 0.00692
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.7% , percentile 52: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 52% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Only applies if your dependency tree includes gov.nsa.emissary:emissary (Maven) < 8.39.0, fixed in 8.39.0 . Check your lockfile, including transitive dependencies.

## What it is

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 workflowdispatch 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 packages

- Maven `gov.nsa.emissary:emissary` < 8.39.0 → fixed: 8.39.0

## Affected products (CVE record)

- NationalSecurityAgency emissary: < 8.39.0

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.69% probability of exploitation activity in the next 30 days; percentile 52.

## Sources

- [GitHub Advisory GHSA-3g6g-gq4r-xjm9](https://github.com/advisories/GHSA-3g6g-gq4r-xjm9)
- [CVE.org record CVE-2026-35580](https://www.cve.org/CVERecord?id=CVE-2026-35580)
- [NVD entry CVE-2026-35580](https://nvd.nist.gov/vuln/detail/CVE-2026-35580)
- [github.com](https://github.com/NationalSecurityAgency/emissary/security/advisories/GHSA-3g6g-gq4r-xjm9)
- [github.com](https://github.com/NationalSecurityAgency/emissary/pull/1286)
- [github.com](https://github.com/NationalSecurityAgency/emissary/pull/1288)

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Source page: https://erroneo.us/security/cve/CVE-2026-35580/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt