The uloc_acceptLanguageFromHTTP function in common/uloc.cpp in International Components for Unicode (ICU) through 57.1 for C/C++ does not ensure that there is a '\0' character at the end of a certain temporary array, which allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a call with a long httpAcceptLanguage argument.
http://git.php.net/?p=php-src.git;a=commit;h=aa82e99ed8003c01f1ef4f0940e56b85c5b032d4
http://openwall.com/lists/oss-security/2016/07/24/2
https://security.gentoo.org/glsa/201701-58
https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html