I accidentally logged hundreds of thousands of phone calls to military bases
I accidentally logged phone calls to military bases

A security researcher bought an expired domain for 5€ and gained control of DNS for phone-network infrastructure covering three British territories, including Diego Garcia. Logs revealed hundreds of thousands of ENUM queries for calls to military bases. The researcher reported it to the UK's NCSC, which eventually took over the domain.
A nation state with an interest in what's happening on those bases would have absolutely loved sitting on this for months without anyone noticing.