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.
http://www.securityfocus.com/bid/100538
https://access.redhat.com/errata/RHSA-2018:1296
https://github.com/kkos/oniguruma/commit/9690d3ab1f9bcd2db8cbe1fe3ee4a5da606b8814
Source: MITRE
Published: 2017-05-24
Updated: 2018-05-04
Type: CWE-125
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL