Critical error

[Bigguy]

I have just got a critical error in my error logs. This is the error message, the error itself is to long to post:

Code Select Expand

JSON decode error: Control character error, possibly incorrectly encoded

There are two of them. Both from the same ip. Is this someone trying to break into my site or just a random error. if so why is it critical.

[shawnb61]

Pretty sure this is related to:
https://github.com/SimpleMachines/SMF/issues/7596
and:
https://www.simplemachines.org/community/index.php?topic=584065.0

As near as we can tell, this happens when someone plays around with their browser USER_AGENT and throws an unusual amount of data in there.  That value is stored in a json string in SMF, & becomes too large to fit in some of our logs, e.g., log_online.

This shows up differently depending on the environment: some folks, the value cannot be stored (data too long), and for others, it shows up as a json decode error upon retrieval, because it was truncated.

So...  Based on what we know, it appears harmless, just annoying...  Odds are high that the user/bot affected knows they were dorking around with the USER_AGENT, just to see what might happen.  Fix coming, but more of a 2.1.4 thing.

[Bigguy]

Thank you sir. Just never seen that before. i won't worry about it then.