Customers were sent an email on Wednesday, saying in “very rare cases” Echo Buds could overheat in their charging case.
Amazon said it had released a software update to fix the issue "out of an abundance of caution".
“The safety of our customers is our top priority,” it said.
Amazon would not say if this meant the earphones could catch fire or explode, but did disclose that its investigation had been prompted by a concerned customer getting in touch.
Amazon said owners would automatically receive the update when the Echo Buds were connected via Bluetooth to a mobile phone and the Alexa app