---
id: CVE-2026-78861
title: >-
  An issue in Mercusys AC12 V2 allows a local attacker to execute arbitrary code
  via a hardcoded 512-bit RSA Private Key
summary: >-
  An issue in Mercusys AC12 V2 allows a local attacker to execute arbitrary code
  via a hardcoded 512-bit RSA Private Key
severity: high
cvss: 7.7
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-789
published: '2026-10-05'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T17:17:26.800'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78861'
references:
  - url: 'http://ac12.com'
    label: cve@mitre.org
  - url: 'http://mercusys.com'
    label: cve@mitre.org
  - url: >-
      https://threadpoolx.gitbook.io/docs/cve/mercusys-ac12-v2-security-advisory/hardcoded-private-key
    label: cve@mitre.org
  - url: >-
      https://threadpoolx.gitbook.io/docs/cve/mercusys-ac12-v2-security-advisory/hardcoded-private-key
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00205
epssPercentile: 0.10378
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-06T16:12:39.142341Z'
ingestedAt: '2026-10-05T20:32:56.655Z'
---

## Overview

An issue in Mercusys AC12 V2 allows a local attacker to execute arbitrary code via a hardcoded 512-bit RSA Private Key

## Remediation

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