The resolveImplicitLevels function in common/ubidi.c in the Unicode Bidirectional Algorithm implementation in ICU4C in International Components for Unicode (ICU) before 55.1 does not properly track directionally isolated pieces of text, which allows remote attackers to cause a denial of service (heap-based buffer overflow) or possibly execute arbitrary code via crafted text.

References

• https://nvd.nist.gov/vuln/detail/CVE-2014-8146
• https://raw.githubusercontent.com/pedrib/PoC/master/generic/i-c-u-fail.txt
• https://security.gentoo.org/glsa/201507-04
• https://support.apple.com/HT205212
• https://support.apple.com/HT205213
• https://support.apple.com/HT205221
• https://support.apple.com/HT205267
• https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
• http://bugs.icu-project.org/trac/changeset/37162
• http://lists.apple.com/archives/security-announce/2015/Sep/msg00001.html
• http://lists.apple.com/archives/security-announce/2015/Sep/msg00003.html
• http://lists.apple.com/archives/security-announce/2015/Sep/msg00005.html
• http://lists.apple.com/archives/security-announce/2015/Sep/msg00008.html
• http://openwall.com/lists/oss-security/2015/05/05/6
• http://seclists.org/fulldisclosure/2015/May/14
• http://www.debian.org/security/2015/dsa-3323
• http://www.kb.cert.org/vuls/id/602540
• http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
• http://www.oracle.com/technetwork/topics/security/cpuoct2015-2367953.html
• http://www.securityfocus.com/bid/74457