CVE-2026-35580

CVE-2026-35580 is a critical-severity vulnerability in Nsa Emissary with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-77.

Key facts

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.

Frequently asked questions

What is CVE-2026-35580?
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.
How severe is CVE-2026-35580?
CVE-2026-35580 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-35580 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-35580?
CVE-2026-35580 affects Nsa Emissary. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-35580?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-35580 have an EU (EUVD) identifier?
Yes. CVE-2026-35580 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19728.
When was CVE-2026-35580 published?
CVE-2026-35580 was published on 2026-04-07 and last updated on 2026-06-17.

References

Affected products (1)

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