defamation accused help needed

need advice for a friend.

if someone shared a screenshot on social media that they found circulating online, without knowing it was fake, and it ended up going viral beyond what they expected, and now they can’t trace back the original source they got it from - what kind of legal exposure could they have under Indian law? particularly around defamation.

the post has since been deleted within 15 minutes, no ongoing harm caused by them directly. just trying to understand the legal landscape and whether the person who shared it (not created it) has the same liability as the original creator

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