CVE-2026-25781 Overview
CVE-2026-25781 affects OpenHarmony v6.0 and prior versions. A local attacker with low privileges can trigger an out-of-bounds write [CWE-787] that causes an unrecoverable denial of service condition. The flaw crosses a security scope boundary, allowing impact beyond the attacker's initial privilege context. OpenHarmony powers a broad range of smart devices, making the affected install base significant in IoT and embedded deployments.
Critical Impact
A local low-privileged process can corrupt memory in OpenHarmony v6.0, causing a permanent denial of service that cannot be recovered without reimaging or full system intervention.
Affected Products
- OpenHarmony v6.0
- OpenHarmony versions prior to v6.0
- Devices and embedded systems based on the affected OpenHarmony releases
Discovery Timeline
- 2026-05-19 - CVE CVE-2026-25781 published to NVD
- 2026-05-19 - Last updated in NVD database
Technical Details for CVE-2026-25781
Vulnerability Analysis
The vulnerability is an out-of-bounds write [CWE-787] in OpenHarmony v6.0 and earlier. A local attacker with low privileges can write data outside the bounds of an allocated buffer. The write corrupts adjacent memory regions used by privileged or system components, leading to a denial of service. The advisory states the condition cannot be recovered, which indicates the corruption persists across recovery attempts or damages state required for normal boot or operation.
The scope is classified as changed, meaning the vulnerable component and the impacted component differ. A process running with limited privileges can affect resources owned by another security authority. Confidentiality and integrity are both impacted at a high level, indicating the write primitive may also enable disclosure or tampering of protected data, not solely a crash.
Root Cause
The root cause is improper bounds checking on a write operation within an OpenHarmony component. The code path accepts attacker-influenced input and computes a destination offset or length without validating it against the destination buffer size. See the OpenHarmony Security Disclosure for the affected component details.
Attack Vector
Exploitation requires local access and low privileges. No user interaction is needed. An attacker delivers crafted input through an interprocess communication interface, system call, or service entry point exposed to unprivileged callers. The malformed input triggers the out-of-bounds write, corrupting memory and producing an unrecoverable DoS state on the device.
No public proof-of-concept code is available. The vulnerability is described in prose only in the vendor advisory.
Detection Methods for CVE-2026-25781
Indicators of Compromise
- Unexpected crashes, panics, or reboot loops in OpenHarmony services or system processes on v6.0 devices
- Devices failing to complete boot after a local application execution, requiring reflashing or factory recovery
- Kernel or HiLog entries indicating memory corruption, segmentation faults, or aborts in system components shortly after invocation by a low-privileged process
Detection Strategies
- Monitor OpenHarmony device logs for repeated abort signals (SIGSEGV, SIGABRT) originating from system services after IPC calls from unprivileged apps
- Inspect application installs and runtime behavior for processes issuing malformed parameters to system service interfaces
- Correlate sudden device unavailability with prior local execution of unverified or sideloaded applications
Monitoring Recommendations
- Centralize OpenHarmony device telemetry and crash dumps for fleet-wide anomaly review
- Alert on devices that enter unrecoverable states requiring reimaging, which can indicate exploitation of this class of memory corruption
- Track installation of unsigned or untrusted application packages on managed OpenHarmony endpoints
How to Mitigate CVE-2026-25781
Immediate Actions Required
- Inventory all OpenHarmony devices and identify systems running v6.0 or earlier
- Restrict installation of untrusted local applications on affected devices until a patch is applied
- Apply the vendor security update referenced in the OpenHarmony May 2026 disclosure as soon as it is available for your device platform
Patch Information
OpenHarmony has published the disclosure in its monthly security advisory. Refer to the OpenHarmony Security Disclosure for May 2026 for the patch commit references and affected component fixes. Device vendors that build downstream distributions on OpenHarmony must integrate the upstream fix and ship updated firmware to end users.
Workarounds
- Limit local code execution to signed, verified applications through device management policies
- Disable or restrict access to non-essential system service interfaces exposed to unprivileged apps
- Apply application allowlisting on managed OpenHarmony devices until firmware updates are deployed
# Configuration example: verify OpenHarmony version on a device
hdc shell param get const.ohos.fullname
# Compare reported version against v6.0 and prior; upgrade if affected
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
