---
id: CVE-2026-61554
title: emp3r0r is a C2 designed by Linux users for Linux environments
summary: >-
  emp3r0r is a C2 designed by Linux users for Linux environments. Prior to
  version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP
  polling sessions before CBOR `MsgAuth` authentication is completed. A remote
  unauthenti…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
vendor: jm33-m0
product: github.com/jm33-m0/emp3r0r/core
affected:
  - github.com/jm33-m0/emp3r0r/core < 0.0.0-20260531142011-aed3d81641ab
patched:
  - github.com/jm33-m0/emp3r0r/core 0.0.0-20260531142011-aed3d81641ab
published: '2026-09-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:17:22.020'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-61554'
references:
  - url: 'https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5'
    label: security-advisories@github.com
  - url: 'https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34'
    label: security-advisories@github.com
  - url: 'https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-4595-rvpx-4q34'
  - url: 'https://github.com/jm33-m0/emp3r0r'
tags:
  - nvd
  - ghsa
  - go
  - cve.org
  - osv
  - exploit-available
aliases:
  - GHSA-4595-rvpx-4q34
ecosystem: go
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-16T17:59:27.422568Z'
ingestedAt: '2026-09-15T21:44:50.635Z'
epss: 0.00707
epssPercentile: 0.51375
---

## Overview

emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing. Version 4.2.5 patches the issue.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-61554)

Affected packages:

- `github.com/jm33-m0/emp3r0r/core < 0.0.0-20260531142011-aed3d81641ab`

Patched in:

- `github.com/jm33-m0/emp3r0r/core 0.0.0-20260531142011-aed3d81641ab`

Source: https://github.com/advisories/GHSA-4595-rvpx-4q34