CVE-2026-71265

Description

A flaw was found in Domoticz. The MochadTCP component in Domoticz contains a stack buffer overflow vulnerability. This flaw occurs when the MatchLine() handler processes MOCHAD_RFSEC messages, copying network-received data into a fixed-size buffer without proper length checks. A remote attacker on the local network, able to reach the Mochad TCP bridge, could send a crafted packet to overflow this buffer, potentially leading to arbitrary code execution or denial of service (DoS).

Statement

Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.

Mitigation

Restrict network access to the Domoticz Mochad TCP bridge on port 1099. Configure a firewall to allow connections only from trusted hosts or disable the Mochad TCP bridge feature within Domoticz if it is not actively used. For example, using `firewall-cmd` to limit access: `firewall-cmd --permanent --add-rich-rule='rule family="ipv4" port port="1099" protocol="tcp" source address="<TRUSTED_IP_OR_NETWORK>" accept'` followed by `firewall-cmd --reload`. If disabling the feature in Domoticz, a service restart may be required.

Understanding the Weakness (CWE)

CWE-120

Integrity,Confidentiality,Availability

Technical Impact: Modify Memory; Execute Unauthorized Code or Commands

Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of the product's implicit security policy. This can often be used to subvert any other security service.

Availability

Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)

Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the product into an infinite loop.

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