CVE-2026-35582

HighPublic PoC

Published: 18 April 2026

Published

18 April 2026

Modified

24 April 2026

KEV Added

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Patch

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CVSS Score 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS Score 0.0006 18.7th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-35582 is a high-severity OS Command Injection (CWE-78) vulnerability in Nsa Emissary. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Unix Shell (T1059.004); ranked at the 18.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Unix Shell (T1059.004) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly requires validation and sanitization of IN_FILE_ENDING and OUT_FILE_ENDING configuration inputs to block shell metacharacters before interpolation into /bin/sh -c commands.

SI-2 Flaw Remediation good match

prevent

Mandates identification, reporting, and correction of the specific OS command injection flaw by upgrading to Emissary version 8.43.0.

CM-5 Access Restrictions for Change partial match

prevent

Restricts who can write or modify .cfg files, mitigating exploitation by adversaries with place configuration authorship privileges.

MITRE ATT&CK Enterprise TechniquesAI

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

Why these techniques?

OS command injection via unsanitized config values into /bin/sh -c directly enables Unix shell command execution (T1059.004); local attack vector with scope change and elevated JVM privileges also facilitates exploitation for privilege escalation (T1068).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

Emissary is a P2P based data-driven workflow engine. In versions 8.42.0 and below, Executrix.getCommand() is vulnerable to OS command injection because it interpolates temporary file paths into a /bin/sh -c shell command string without any escaping or input validation. The…

IN_FILE_ENDING and OUT_FILE_ENDING configuration keys flow directly into these paths, allowing a place author who can write or modify a .cfg file to inject arbitrary shell metacharacters that execute OS commands in the JVM process's security context. The framework already sanitizes placeName via an allowlist before embedding it in the same shell string, but applies no equivalent sanitization to file ending values. No runtime privileges beyond place configuration authorship, and no API or network access, are required to exploit this vulnerability. This is a framework-level defect with no safe mitigation available to downstream implementors, as Executrix provides neither escaping nor documented preconditions against metacharacters in file ending inputs. This issue has been fixed in version 8.43.0.

Deeper analysisAI

CVE-2026-35582 is an OS command injection vulnerability (CWE-78, CWE-116) in Emissary, a P2P-based data-driven workflow engine developed by the National Security Agency. The issue affects versions 8.42.0 and below, specifically in the Executrix.getCommand() method, which interpolates temporary file paths derived from the IN_FILE_ENDING and OUT_FILE_ENDING configuration keys directly into a /bin/sh -c shell command string without escaping or input validation. While the framework sanitizes the placeName via an allowlist, it applies no equivalent checks to these file ending values, enabling injection of arbitrary shell metacharacters through manipulation of .cfg files.

An attacker with place configuration authorship privileges—who can write or modify a .cfg file—can exploit this vulnerability locally without requiring runtime privileges beyond that access, API calls, or network connectivity. Successful exploitation allows execution of arbitrary OS commands within the JVM process's security context, potentially leading to high confidentiality, integrity, and availability impacts (CVSS 8.8: AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H). The scope is changed due to the elevated privileges gained in the JVM environment.

The vulnerability has been addressed in Emissary version 8.43.0, as detailed in the GitHub security advisory (GHSA-3p24-9x7v-7789) and the fixing commit (1faf33f2494c0128f250d7d2e8f2da99bbd32ae8). No safe workarounds exist for downstream users, as the framework lacks escaping mechanisms or documented restrictions on metacharacters in file ending inputs. Security practitioners should upgrade to 8.43.0 or later.