VDB-413803 · CVE-2026-78861 · GCVE-0-2026-78861

Mercusys AC12 hard-coded credentials

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.2	$0-$5k	1.35

Summaryinfo

A vulnerability was found in Mercusys AC12. It has been classified as very critical. Impacted is an unknown function. This manipulation causes hard-coded credentials. This vulnerability appears as CVE-2026-78861. The attack requires local access. There is no available exploit.

Detailsinfo

A vulnerability classified as very critical was found in Mercusys AC12 (unknown version). Affected by this vulnerability is an unknown code block. The manipulation with an unknown input leads to a hard-coded credentials vulnerability. The CWE definition for the vulnerability is CWE-798. The product contains hard-coded credentials, such as a password or cryptographic key, which it uses for its own inbound authentication, outbound communication to external components, or encryption of internal data. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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

This vulnerability is known as CVE-2026-78861 since 08/25/2026. The exploitation appears to be easy. Attacking locally is a requirement. Additional levels of successful authentication are necessary for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/05/2026). The attack technique deployed by this issue is T1110.001 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Mercusys

Name

AC12

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.2

VulDB Base Score: 8.2
VulDB Temp Score: 8.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Hard-coded credentials
CWE: CWE-798 / CWE-259 / CWE-255
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/25/2026 CVE reserved
10/05/2026 +41 days Advisory disclosed
10/05/2026 +0 days VulDB entry created
10/05/2026 +0 days VulDB entry last update

Sourcesinfo

Status: Not defined

CVE: CVE-2026-78861 (🔒)
GCVE (CVE): GCVE-0-2026-78861
GCVE (VulDB): GCVE-100-413803

Entryinfo

Created: 10/05/2026 22:28
Changes: 10/05/2026 22:28 (49)
Complete: 🔍
Cache ID: 216::103