CVE-2026-78861 Mercusys AC12 - Remote Code Execution

Mercusys AC12 V2 contains a remote code execution caused by a hardcoded 512-bit RSA Private Key, letting local attackers execute arbitrary code, exploit requires local access.

CVSS base score 7.7 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.14% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Remote Code Execution
Impact
Remote Code Execution
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published
5 October 2026
Updated
15 October 2026
Weakness
CWE-789

Vendor fix

Update to the latest version with the hardcoded key removed.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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