"For a brief period today, a message meant for memorialized profiles was mistakenly posted to other accounts," a Facebook spokesperson said.
"This was a terrible error that we have now fixed."
Media reports indicated that some two million errant memorials were posted on profile pages.
Even Facebook co-founder and chief executive Zuckerberg was memorialized in a message at his profile page expressing hope that people who loved him would take comfort in posts people shared in tribute to his life.
"Poor Mark," read an @JudiD23 tweet that included weeping face emojis.
"Couldn't happen to a nicer guy."
The social network apologized and said it worked as quickly as possible to correct the problem. It has now been fixed.