Is CVE-2026-78861 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-78861 being exploited in the wild.

How severe is CVE-2026-78861?

Informational severity, published 5 October 2026.

Is there a fix for CVE-2026-78861?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-78861 attacked?

It is attacked with local access.

Am I affected by CVE-2026-78861?

Check whether you run Mercusys AC12 V2. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-78861: Mercusys AC12 V2 hardcoded RSA private key code execution

CVE-2026-78861 · Severity: info · Published 2026-10-05

The Mercusys AC12 V2 is a wireless router used in home and small office networks. The device contains a hardcoded 512-bit RSA private key that an attacker with local access can use to impersonate the device and execute arbitrary code, potentially compromising the network and any connected devices.

Technologies: Mercusys AC12 V2. Vendors: Mercusys.

Quick answers

Is CVE-2026-78861 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-78861 being exploited in the wild.
How severe is CVE-2026-78861?: Informational severity, published 5 October 2026.
Which products and versions are affected?: Mercusys AC12 V2.
Is there a fix for CVE-2026-78861?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-78861 attacked?: It is attacked with local access.
Am I affected by CVE-2026-78861?: Check whether you run Mercusys AC12 V2. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The AC12 V2 router embeds a hardcoded RSA private key in its firmware, allowing local attackers to forge cryptographic signatures or decrypt sensitive communications. The vulnerability requires local access to the device or its firmware; recovery of the private key enables arbitrary code execution with device privileges.

Affected products

Mercusys AC12 V2

Timeline

2026-10-05: disclosed

References

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