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.
http://www.securityfocus.com/bid/101244
https://access.redhat.com/errata/RHSA-2018:1296
https://github.com/kkos/oniguruma/commit/690313a061f7a4fa614ec5cc8368b4f2284e059b
Source: MITRE
Published: 2017-05-24
Updated: 2018-10-31
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