Harmonyos EUVD-2026-21800

Local attacker without privileges can exploit this Use-After-Free vulnerability in the communication module. No user interaction required. Requires local system access to trigger the vulnerable code path in the affected communication module.

Real-world risk assessment presents a nuanced profile. The CVSS 3.1 score of 7.3 (High) reflects the technical severity with an attractive attack profile: local access required (AV:L) but no authentication needed (PR:N), low complexity (AC:L), and no user interaction required (UI:N). The impact shows high availability disruption (A:H) with low confidentiality and integrity impacts (C:L/I:L), suggesting denial-of-service as primary concern with potential for limited information disclosure. However, several factors moderate immediate priority: the local attack vector limits remote exploitation, requiring physical or logical access to the device; no EPSS data available for probability assessment; no public exploit identified at time of analysis; and no CISA KEV listing indicating active exploitation. The race condition nature (CWE-362) suggests exploitation complexity may be higher than AC:L indicates, as timing windows can be difficult to reliably trigger. For HarmonyOS deployments in consumer wearables and mobile devices, this represents a medium-to-high priority requiring timely patching during normal maintenance cycles, elevated to high priority for enterprise or sensitive deployments where local access by untrusted users is possible.

An attacker with local access to a HarmonyOS device (such as a malicious application installed with limited permissions, or physical access to an unlocked device) could exploit this race condition without requiring authentication. The attacker would trigger concurrent operations in the communication module to create a race window where memory is freed and reallocated. By winning the race, the attacker manipulates the use-after-free condition to cause a system crash or denial of service, disrupting device availability. With precise timing and memory manipulation, the attacker might also read limited sensitive data from freed memory regions before they are overwritten, achieving low-level information disclosure. No public exploit identified at time of analysis, but the low attack complexity suggests feasibility for skilled attackers.