Mastra NPM Supply Chain Attack: 140 Packages Backdoor via easy-day-JS Typosquat (opens in new tab)

On June 17, 2026, an attacker compromised the @mastra npm organization and quietly added easy-day-js as a dependency across 140+ packages in the Mastra AI framework ecosystem. easy-day-js is a typosquat of the popular dayjs date library, and its latest version contained an obfuscated postinstall dropper that downloaded and ran a second-stage payload from attacker-controlled servers, then deleted itself to remove any trace. Packages with a combined weekly download count exceeding 1.1 million w...