OpenClaw versions prior to 2026.3.28 lack validation of sender authorization for inbound media sent via Zalo channels. As a result, an unauthenticated or unauthorized sender can trigger the application to fetch media from arbitrary URLs and store the returned data on disk. The data is stored even though the originating message is rejected, effectively allowing an attacker to cause unsolicited network requests and write arbitrary content to the media store, potentially leaking sensitive information or overwriting critical files.

Current users of OpenClaw running any version earlier than 2026.3.28 are susceptible to this flaw. The vulnerability applies to the standard OpenClaw distribution on all platforms where the Zalo channel integration is enabled.

The CVSS score of 6.9 indicates a moderate to high risk. Although EPSS data is unavailable and the issue is not listed in KEV, the lack of authorization checks means the flaw can be exploited by sending crafted messages through the Zalo channel. The attack vector is inferred to be through Zalo channel messages that are processed by the OpenClaw service; an attacker only needs to send a manipulated message to trigger the download. The potential impact includes unauthorized data exposure, unauthorized disk writes, and possible denial of service through resource exhaustion.