CVE-2026-44094 Overview
CVE-2026-44094 describes a firmware fallback flaw that lets an unauthenticated remote attacker force an affected device to boot into a secondary firmware partition. That partition ships with an insecure configuration and default credentials. Once the device falls back, the attacker can log in over SSH as the unprivileged local account user-app. The advisory also notes that charging operations can be interrupted, indicating the affected device is an electric vehicle charging or similar embedded system. The issue is tracked under CWE-636: Not Failing Securely (Failing Open) and was published in the CERT-VDE Security Advisory VDE-2026-008.
Critical Impact
An unauthenticated network attacker can trigger a firmware rollback and obtain SSH shell access using default credentials, disrupting device availability including charging sessions.
Affected Products
- Embedded device firmware referenced in CERT-VDE advisory VDE-2026-008
- Specific vendor and product identifiers were not published in the NVD record at the time of writing
- Refer to the CERT-VDE advisory for the authoritative affected product list
Discovery Timeline
- 2026-07-30 - CVE-2026-44094 published to NVD
- 2026-07-30 - Last updated in NVD database
Technical Details for CVE-2026-44094
Vulnerability Analysis
The affected device stores multiple firmware partitions and supports a fallback mechanism intended for recovery scenarios. An unauthenticated remote attacker can trigger this fallback path over the network. The system then boots a partition whose configuration was never hardened for production use. That partition retains default credentials and an SSH service reachable on the network.
After fallback, the attacker authenticates over SSH as the local account user-app. This account is unprivileged, so the attacker does not immediately gain root. However, shell access on the device is sufficient to interrupt charging and to stage further local privilege escalation research. The advisory categorizes the underlying weakness as [CWE-636], meaning the system does not fail securely when it degrades to the recovery image.
Root Cause
The root cause is an insecure-by-default recovery firmware partition combined with an attacker-reachable fallback trigger. The recovery image was shipped with default credentials and an active SSH daemon. The fallback logic does not require authentication or physical presence, so the security posture of the device collapses to the weakest partition on the device.
Attack Vector
The attack vector is network-based and requires no prior credentials or user interaction. The attacker sends the input required to force the system into the fallback firmware, waits for the device to reboot into the recovery partition, and then connects over SSH using the documented default credentials for user-app. The result is a remote shell on the device and an interruption of any active charging session. See the CERT-VDE advisory for vendor-specific technical details.
Detection Methods for CVE-2026-44094
Indicators of Compromise
- Unexpected device reboots followed by a firmware version string matching the recovery or fallback partition.
- SSH authentication events for the local user user-app, particularly from external or non-management networks.
- Charging sessions terminating without a corresponding operator or user action in backend logs.
Detection Strategies
- Monitor device firmware version telemetry and alert when a unit transitions from the primary partition to the fallback partition outside of a planned maintenance window.
- Baseline SSH access to embedded chargers and flag any interactive session, especially for the user-app account.
- Correlate charging-session interruptions with device management-plane events to identify forced fallbacks.
Monitoring Recommendations
- Forward SSH, boot, and firmware-partition logs from affected devices into a centralized SIEM for retention and correlation.
- Alert on repeated network requests to management interfaces that precede an unscheduled reboot.
- Track outbound connections initiated by devices after a fallback event, since a successful login often leads to attacker tooling being pulled onto the device.
How to Mitigate CVE-2026-44094
Immediate Actions Required
- Restrict network access to device management and SSH ports so that only trusted management hosts can reach affected chargers.
- Inventory deployed devices and confirm which firmware partition each unit is currently running.
- Force any unit currently on the fallback partition back to the hardened primary partition and rotate credentials.
Patch Information
Refer to the CERT-VDE Security Advisory VDE-2026-008 for the vendor's fixed firmware versions and update procedure. Apply the vendor-supplied firmware update to both the primary and fallback partitions so that the recovery image no longer contains default credentials.
Workarounds
- Place affected devices behind a network segment that blocks inbound access from untrusted networks to management and SSH services.
- Disable or firewall the SSH service on the device where operational requirements allow.
- Change default credentials on all firmware partitions, including recovery images, if the vendor exposes a mechanism to do so.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
