Info
When MongoDB reads the hostname, it does not ensures that the hostname in question contains valid UTF-8. Drivers may then report errors when trying to run commands that report back this hostname verbatim while trying to decode the string back from UTF-8.
Validated on Linux hostnam? 5.15.0-1020-aws #24-Ubuntu SMP Thu Sep 1 16:05:45 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux but likely applicable to all operating systems that don't directly validate hostname strings.
Steps to Reproduce
#include
int main() {
sethostname("hostnam\xff", 8);
}
gcc -o test test.c
sudo ./test
npx mongodb-runner start -t standalone --version=8.0.x -- --port=27017
# alternative: download + start server manually
# observe failures:
mongosh localhost:27017/admin --eval 'db.aggregate([{ $currentOp: {} }])'
# or:
mongosh localhost:27017/admin --eval 'db.adminCommand({ hostInfo: 1 })'
