CVE-2026-42438 affects OpenClaw versions 2026.4.9 before 2026.4.10, containing a sender policy bypass vulnerability in the outbound host-media attachment read helper. This vulnerability allows unauthorized local file disclosure where attackers with denied read access via toolsBySender or group policy can trigger host-media attachment loading. The flaw enables bypassing sender and group-scoped authorization boundaries to retrieve readable local files through the outbound media path. The vulnerability has been patched in version 2026.4.10 with fixes available through GitHub commits and security advisories.