CVE-2017-9227: Oniguruma Project Oniguruma

Critical severity, CVSS 9.8. EPSS: 6.3% 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 mbc_enc_len() during regular expression searching. Invalid handling of reg->dmin in forward_search_range() could result in an invalid pointer dereference, as an out-of-bounds read from a stack buffer.

Affected products

• Oniguruma Project Oniguruma: version 6.2.0 only
• PHP PHP: from 5.6.0, 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.