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

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-07 · updated 2026-10-26
Weakness: CWE-77

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

NationalSecurityAgency emissary: from 5.10.0 through 8.38.0

References

https://github.com/NationalSecurityAgency/emissary/pull/1286
https://github.com/NationalSecurityAgency/emissary/pull/1288
https://github.com/NationalSecurityAgency/emissary/security/advisories/GHSA-3g6g-gq4r-xjm9

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