Description
An issue was discovered in Oniguruma 6.2.0, as used in Oniguruma-mod in Ruby through 2.4.1 and mbstring in PHP through 7.1.5. A heap out-of-bounds write or read occurs in next_state_val() during regular expression compilation. Octal numbers larger than 0xff are not handled correctly in fetch_token() and fetch_token_in_cc(). A malformed regular expression containing an octal number in the form of '\700' would produce an invalid code point value larger than 0xff in next_state_val(), resulting in an out-of-bounds write memory corruption.
Remediation
References
Related Vulnerabilities
WordPress 4.9.x Multiple Vulnerabilities (4.9 - 4.9.15)
PHP error logging format string vulnerability
WordPress Plugin Are You a Human-The Fun Spam Blocker Cross-Site Scripting (1.4.32)
Oracle Database Server CVE-2007-5514 Vulnerability (CVE-2007-5514)
Perl Improper Link Resolution Before File Access ('Link Following') Vulnerability (CVE-2018-12015)