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Emissary CVE-2021-32647

CRITICAL
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)
2021-06-01 security-advisories@github.com
9.1
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Input neutralization, injection prevention
Impact

CVSS score of 9.1 (CRITICAL). Attack characteristics: network attack vector, low complexity, high privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.
Patch available 2.9% exploitation probability (EPSS)

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AnalysisAI

Emissary is a P2P based data-driven workflow engine. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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Technical ContextAI · show details

This vulnerability is classified under CWE-74. Emissary is a P2P based data-driven workflow engine. Affected versions of Emissary are vulnerable to post-authentication Remote Code Execution (RCE). The CreatePlace REST endpoint accepts an sppClassName parameter which is used to load an arbitrary class. This class is later instantiated using a constructor with the following signature: <constructor>(String, String, String). An attacker may find a gadget (class) in the application classpath that could be used to achieve Remote Code Execution (RCE) or disrupt the application. Even though the chances to find a gadget (class) that allow arbitrary code execution are low, an attacker can still find gadgets that could potentially crash the application or leak sensitive data. As a work around disable network access to Emissary from untrusted sources. Affected products include: Nsa Emissary.

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Severity by source

NVD PRIMARY 9.1 CRITICAL
AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

Emissary is a P2P based data-driven workflow engine. Affected versions of Emissary are vulnerable to post-authentication Remote Code Execution (RCE). The CreatePlace REST endpoint accepts an sppClassName parameter which is used to load an arbitrary class. This class is later instantiated using a constructor with the following signature: <constructor>(String, String, String). An attacker may find a gadget (class) in the application classpath that could be used to achieve Remote Code Execution (RCE) or disrupt the application. Even though the chances to find a gadget (class) that allow arbitrary code execution are low, an attacker can still find gadgets that could potentially crash the application or leak sensitive data. As a work around disable network access to Emissary from untrusted sources.

Threat Intelligence Overview

EPSS Score
2.9%
Top 15% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC Yes
EPSS 2.9%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity + public POC available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

69
Low Medium High Critical
KEV: 0
EPSS: +3
CVSS: +46
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)NVD

cpe:2.3:a:nsa:emissary:6.4.0:*:*:*:*:*:*:*
CVE-2021-32639 CRITICAL POC
9.9 Jul 02

Emissary is a P2P-based, data-driven workflow engine. Rated critical severity (CVSS 9.9), this vulnerability is remotely

CVE-2021-32096 HIGH POC
8.8 May 07

The ConsoleAction component of U.S. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authe

CVE-2021-32093 MEDIUM POC
6.5 May 07

The ConfigFileAction component of U.S. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low

CVE-2021-32092 MEDIUM POC
6.1 May 07

A Cross-site scripting (XSS) vulnerability in the DocumentAction component of U.S. Rated medium severity (CVSS 6.1), thi

CVE-2026-35580 CRITICAL
9.1 Apr 07

Shell command injection in Emissary workflow engine below version 8.39.0 allows high-privileged attackers with repositor

CVE-2021-32094 HIGH
8.8 May 07

U.S. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch

CVE-2021-32095 HIGH
8.1 May 07

U.S. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch

CVE-2026-35581 HIGH
7.2 Apr 07

Command injection in NSA Emissary P2P workflow engine (versions prior to 8.39.0) allows authenticated remote administrat

CVE-2021-32634 HIGH
7.2 May 21

Emissary is a distributed, peer-to-peer, data-driven workflow framework. Rated high severity (CVSS 7.2), this vulnerabil

CVE-2026-35583 MEDIUM
5.3 Apr 07

Emissary versions prior to 8.39.0 allow unauthenticated remote attackers to read arbitrary configuration files through p

CVE-2026-35571 MEDIUM
4.8 Apr 07

Stored cross-site scripting in Emissary prior to 8.39.0 allows authenticated administrators to inject malicious javascri

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