CVE-2017-9226: Oniguruma Project Oniguruma

Critical severity, CVSS 9.8. EPSS: 7.5% chance of exploitation in the next 30 days.

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.

Affected products

• Oniguruma Project Oniguruma: version 6.2.0 only
• PHP PHP: before 5.6.31 (fixed in 5.6.31); from 7.0.0, before 7.0.21 (fixed in 7.0.21); from 7.1.0, before 7.1.7 (fixed in 7.1.7)

Published 2017-05-24. Last modified 2026-06-17.