CVE-2026-24921 Overview
CVE-2026-24921 is an out-of-bounds read vulnerability affecting the HDC (HarmonyOS Device Connector) module in Huawei HarmonyOS. This memory corruption flaw allows a local attacker with low privileges to read memory beyond the intended boundaries, potentially exposing sensitive information and causing service disruption.
The vulnerability stems from improper memory address validation within the HDC module, which handles device connectivity and communication functions. Successful exploitation enables attackers to access confidential data stored in adjacent memory regions and trigger denial of service conditions.
Critical Impact
Successful exploitation of this vulnerability will affect availability and confidentiality of HarmonyOS devices, potentially exposing sensitive user data and causing system instability.
Affected Products
- Huawei HarmonyOS 6.0.0
- HarmonyOS-based smartphones and tablets
- HarmonyOS-based laptops and wearable devices
Discovery Timeline
- February 6, 2026 - CVE-2026-24921 published to NVD
- February 10, 2026 - Last updated in NVD database
Technical Details for CVE-2026-24921
Vulnerability Analysis
This out-of-bounds read vulnerability (CWE-125) exists within the HDC module of HarmonyOS. The HDC module provides essential functionality for device connectivity, debugging, and inter-process communication on HarmonyOS devices.
The flaw occurs when the HDC module processes memory addresses without proper boundary validation. An attacker operating locally with low privileges can craft malicious input that causes the module to read memory locations outside the intended buffer boundaries. This improper memory access can reveal sensitive information from adjacent memory regions, including potentially privileged data, cryptographic material, or system configuration details.
The local attack vector requires the attacker to have existing access to the device, though only low-level privileges are needed to trigger the vulnerability. No user interaction is required for exploitation, making this vulnerability particularly concerning for multi-user device scenarios.
Root Cause
The root cause of CVE-2026-24921 lies in insufficient bounds checking within the HDC module's memory access routines. When processing certain operations, the module fails to properly validate that requested memory addresses fall within allocated buffer boundaries. This allows read operations to extend beyond the intended memory region, violating memory safety guarantees.
The absence of proper input validation and boundary enforcement enables attackers to specify memory offsets that exceed buffer limits, resulting in unauthorized memory disclosure.
Attack Vector
The attack requires local access to a HarmonyOS device. An attacker with low privileges can interact with the HDC module through its exposed interfaces, providing specially crafted input designed to trigger the out-of-bounds read condition.
The exploitation process involves:
- Gaining local access to a target HarmonyOS device
- Interacting with the HDC module through available system interfaces
- Supplying malicious input that bypasses incomplete boundary checks
- Reading sensitive data from memory regions adjacent to the intended buffer
- Optionally causing service disruption through memory access violations
The vulnerability does not require elevated privileges or user interaction, though it is limited to local exploitation scenarios. The impact is constrained to confidentiality and availability; no integrity impact has been identified.
Detection Methods for CVE-2026-24921
Indicators of Compromise
- Unexpected crashes or restarts of HDC-related services on HarmonyOS devices
- Anomalous memory access patterns in system logs associated with the HDC module
- Unusual process behavior or memory consumption from HDC-dependent applications
- Debug or error messages indicating out-of-bounds memory access attempts
Detection Strategies
- Monitor system logs for HDC module errors, crashes, or memory access violations
- Deploy endpoint detection solutions capable of identifying memory corruption exploitation attempts
- Implement application whitelisting to restrict unauthorized interactions with HDC module interfaces
- Use behavioral analysis to detect anomalous memory read patterns on HarmonyOS devices
Monitoring Recommendations
- Enable verbose logging for HarmonyOS system services to capture potential exploitation attempts
- Configure alerts for repeated HDC module failures or unexpected service restarts
- Monitor device telemetry for unusual memory consumption patterns
- Establish baseline behavior for HDC module operations to identify deviations
How to Mitigate CVE-2026-24921
Immediate Actions Required
- Apply the latest HarmonyOS security updates from Huawei immediately
- Review device access controls and restrict local access to trusted users only
- Enable automatic security updates on all HarmonyOS devices
- Audit systems for signs of potential exploitation using the detection strategies outlined above
Patch Information
Huawei has released security patches addressing CVE-2026-24921 in their February 2026 security bulletins. Organizations and users should apply these updates to all affected HarmonyOS devices as soon as possible.
Official security bulletins are available at:
Users should navigate to Settings → System → Software update to check for and install available security patches.
Workarounds
- Restrict physical and local access to HarmonyOS devices to trusted personnel only
- Disable or restrict HDC functionality if not required for device operation (typically used for development and debugging)
- Implement network segmentation to isolate potentially vulnerable devices
- Monitor for suspicious local activity on devices pending patch deployment
# Check current HarmonyOS version and security patch level
# Navigate to: Settings → About device → Version
# Ensure the security patch level is dated February 2026 or later
# Enable automatic updates
# Settings → System → Software update → Auto-download over Wi-Fi
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
