The ucnv_UTF8FromUTF8 function in ucnv_u8.cpp in International Components for Unicode (ICU) for C/C++ through 60.1 mishandles ucnv_convertEx calls for UTF-8 to UTF-8 conversion, which allows remote attackers to cause a denial of service (stack-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted string, as demonstrated by ZNC.
https://github.com/znc/znc/issues/1459
https://ssl.icu-project.org/trac/attachment/ticket/13490/poc.cpp
https://ssl.icu-project.org/trac/changeset/40714
https://ssl.icu-project.org/trac/changeset/40715
https://ssl.icu-project.org/trac/ticket/13490
https://ssl.icu-project.org/trac/ticket/13510
https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
Source: MITRE
Published: 2017-12-10
Updated: 2019-04-23
Type: CWE-119
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL