Shell Command Execution Vulnerability in Cosmicstack Labs Mercury Agent
CVE-2026-90813

5.3MEDIUM

Key Information:

Vendor

Cosmicstack-labs

Status
Mercury-agent
Vendor
CVE Published:
14 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-90813?

A vulnerability in the Cosmicstack Labs Mercury Agent allows for improper handling of shell commands due to an incorrect order of validation and canonicalization. The issue is present in the function checkShellCommand within the src/capabilities/permissions.ts file. This flaw can be exploited remotely, potentially allowing attackers to manipulate the execution of shell commands. Despite an early report to the developers, they have not responded to this critical issue, leaving users exposed.

Affected Version(s)

mercury-agent 1.1.0

mercury-agent 1.1.1

mercury-agent 1.1.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-90813 - Proof of Concept

References

https://vuldb.com/vuln/403315
vdb-entrytechnical-description
https://vuldb.com/vuln/403315/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-90813
third-party-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Eric-a (VulDB User)
VulDB CNA Team
.