CVE-2026-27814 Overview
CVE-2026-27814 is a race condition vulnerability in EVerest, an open-source EV charging software stack. The vulnerability involves a data race (C++ undefined behavior) that is triggered when a 1-phase to 3-phase switch request (ac_switch_three_phases_while_charging) executes concurrently with the state machine loop during charging or waiting operations. This concurrent execution creates undefined behavior that could lead to integrity and availability impacts.
Critical Impact
Exploitation of this data race could allow an attacker with adjacent network access to cause integrity violations or service disruption in EV charging operations.
Affected Products
- EVerest versions prior to 2026.02.0
Discovery Timeline
- 2026-03-26 - CVE CVE-2026-27814 published to NVD
- 2026-03-26 - Last updated in NVD database
Technical Details for CVE-2026-27814
Vulnerability Analysis
This vulnerability is classified as CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization), commonly known as a race condition. The flaw exists in the EVerest charging stack's handling of phase switching requests during active charging sessions.
The core issue stems from the ac_switch_three_phases_while_charging function executing without proper synchronization mechanisms when the state machine loop is also accessing shared resources. In C++, this creates undefined behavior (UB), meaning the program's execution becomes unpredictable and can result in memory corruption, incorrect state transitions, or system instability.
Root Cause
The root cause is improper synchronization between the phase switching logic and the charging state machine. When a request to switch between 1-phase and 3-phase charging is initiated while the state machine is actively processing, both code paths access shared charging state data without adequate locking or atomic operations. This violates C++ memory model guarantees and constitutes undefined behavior.
Attack Vector
The vulnerability requires adjacent network access to exploit, meaning an attacker must be on the same local network segment as the EVerest charging controller. Exploitation involves sending precisely timed phase switch requests to trigger the race condition during active charging sessions.
The attack complexity is high due to the timing-dependent nature of race conditions—successful exploitation requires the malicious request to arrive during a specific window when the state machine is processing shared resources. No user interaction or special privileges are required to attempt exploitation.
Successful exploitation could result in:
- Incorrect charging state transitions
- Potential integrity issues with charging session data
- Service disruption affecting charging availability
Detection Methods for CVE-2026-27814
Indicators of Compromise
- Unexpected phase switching behavior during active charging sessions
- Abnormal state machine transitions logged in EVerest system logs
- Charging session interruptions without user-initiated stop requests
- Inconsistent charging state data between system components
Detection Strategies
- Monitor EVerest logs for unusual ac_switch_three_phases_while_charging call patterns during active charging states
- Implement network traffic analysis to detect rapid or malformed phase switch requests from unexpected sources
- Deploy intrusion detection rules to identify anomalous command sequences targeting the charging controller
Monitoring Recommendations
- Enable verbose logging for state machine transitions and phase switching operations
- Implement network segmentation to isolate EV charging infrastructure from untrusted network segments
- Establish baseline behavior patterns for charging sessions to detect anomalies
How to Mitigate CVE-2026-27814
Immediate Actions Required
- Upgrade EVerest to version 2026.02.0 or later, which contains the patch for this vulnerability
- Restrict network access to EVerest charging controllers to trusted management systems only
- Review logs for any signs of exploitation attempts before patching
Patch Information
The EVerest project has released version 2026.02.0 which addresses this data race vulnerability. The patch introduces proper synchronization mechanisms to prevent concurrent access between the phase switching function and the state machine loop. For detailed patch information, refer to the GitHub Security Advisory.
Workarounds
- Implement network-level access controls to restrict which systems can send phase switch commands to the charging controller
- Consider disabling dynamic phase switching functionality if not operationally required until the patch can be applied
- Deploy network monitoring to detect and alert on suspicious activity targeting the charging infrastructure
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
