CVE-2025-56566: MikroTik Firmware Cleartext Storage Flaw

CVE-2025-56566 Overview

CVE-2025-56566 affects MikroTik firmware version 7.19.4. The device stores sensitive authentication credentials and network state in cleartext within non-volatile storage. An attacker with physical access can extract this material from an SPI flash dump. The extraction requires no authentication to the device and no knowledge of the administrative password.

The issue exposes administrative credentials, configuration secrets, and network state that should be protected at rest. Physical possession of the router, or transit access during shipping and RMA, is sufficient to compromise the stored secrets.

Critical Impact
Physical access to a MikroTik device running firmware 7.19.4 allows full recovery of administrative credentials and network configuration through an SPI flash dump, without any authentication.

Affected Products

MikroTik RouterOS firmware version 7.19.4
MikroTik devices using affected SPI flash storage for configuration
Deployments where physical access to devices cannot be guaranteed

Discovery Timeline

2026-09-16 - CVE-2025-56566 published to the National Vulnerability Database
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2025-56566

Vulnerability Analysis

MikroTik firmware 7.19.4 writes sensitive authentication material and network state to non-volatile SPI flash storage without encryption. The stored data includes credentials used to administer the device and configuration values that describe the network the device serves.

An attacker who physically accesses the device can desolder or clip onto the SPI flash chip and read its contents using a standard programmer. The resulting dump contains readable credentials and network state. No login, factory reset bypass, or exploitation of a running service is required.

The vulnerability aligns with Cleartext Storage of Sensitive Information [CWE-312] and Insufficient Protection of Credentials at rest. Because the material is stored unprotected, standard forensic hardware tooling recovers it.

Root Cause

The root cause is a design decision to persist credentials and network state in plaintext on SPI flash. The firmware does not apply device-bound encryption, does not tie secrets to a hardware root of trust, and does not use a secure element to protect at-rest material. Any read of the flash contents returns usable secrets.

Attack Vector

Exploitation requires physical access to the device. The attacker powers the device down, accesses the SPI flash chip on the printed circuit board, and reads its contents with an SPI programmer such as a CH341A or similar tool. The flash image is then parsed offline to extract credentials and configuration values.

Relevant scenarios include stolen or discarded hardware, supply-chain interception, unattended branch-office equipment, and returned RMA units. See the GitHub Security Advisory for CVE-2025-56566 for the technical write-up.

No verified public exploit code is required to reproduce the issue. The attack relies on standard hardware analysis workflows against unprotected flash.

Detection Methods for CVE-2025-56566

Indicators of Compromise

Unexplained physical tampering evidence on device chassis, screws, or tamper-evident seals
Devices returning from RMA, shipping, or long unattended deployments with altered configuration or timestamps
Reuse of administrative credentials from a MikroTik device on other systems, suggesting offline recovery
Unexpected administrator logins from new source addresses following device physical access events

Detection Strategies

Monitor RouterOS authentication logs for logins using known-static administrative credentials after suspected physical access
Correlate configuration changes with maintenance windows and physical inventory checks
Track credential reuse across the network estate to identify secrets extracted from a single device

Monitoring Recommendations

Forward RouterOS syslog and authentication events to a centralized log platform for retention and correlation
Alert on administrative logins from unusual geolocations or outside change windows
Inventory and physically audit deployed MikroTik hardware on a defined cadence
Track device movements and RMA returns as security-relevant events

How to Mitigate CVE-2025-56566

Immediate Actions Required

Treat any MikroTik device running firmware 7.19.4 that has left physical custody as compromised
Rotate all administrative credentials, pre-shared keys, RADIUS secrets, and VPN keys stored on affected devices
Restrict physical access to network equipment using locked enclosures and tamper-evident seals
Review the vendor advisory reference for fixed firmware availability

Patch Information

No patched firmware version is listed in the NVD entry at the time of publication. Monitor MikroTik release notes for a firmware version that addresses cleartext storage of credentials on SPI flash. Apply the fixed release across all affected units when available and rotate secrets after upgrade.

Workarounds

Deploy MikroTik devices only in physically secure locations with controlled access
Use unique administrative credentials per device to limit blast radius of a single flash extraction
Sanitize or destroy SPI flash on decommissioned or returned units before disposal or RMA
Segment management interfaces and require additional network-layer authentication such as VPN plus RADIUS with rotated secrets

bash

# Example: rotate the RouterOS admin password and RADIUS secret after suspected exposure
/user set admin password="<new-strong-password>"
/radius set [find] secret="<new-radius-secret>"
/ip service set winbox address=10.0.0.0/24
/ip service disable telnet,ftp,api