CVE-2017-9224: Oniguruma Project Oniguruma

Critical severity, CVSS 9.8. EPSS: 6.5% 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 stack out-of-bounds read occurs in match_at() during regular expression searching. A logical error involving order of validation and access in match_at() could result in an out-of-bounds read from a stack buffer.

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.