Use to_existing_atom instead of to_atom #75
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duics
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Nov 17, 2025
CRITICAL SECURITY FIX: Use to_existing_atom instead of to_atom when processing ICS files. This prevents atom table exhaustion attacks from untrusted input that could crash the VM. From: lpil#75 Author: nixx quality
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These two functions use
to_atomwhich is inappropriate for untrusted input.Not really a problem in recurrence.ex since it's only accepting rules from the developer as far as I can see, but deserialize.ex takes raw file data, which is definitely untrusted.
I haven't tested it since my Erlang version is too new and there was a breaking change with
ssl_verify_funa while back, but I'm certain it will work.