The CHECK macro in mrbgems/mruby-sprintf/src/sprintf.c in mruby 1.4.1 contains a signed integer overflow, possibly leading to out-of-bounds memory access because the mrbstrresize function in string.c does not check for a negative length.
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2018-14337.json"