An issue was discovered in Oniguruma 6.x before 6.9.4_rc2. In the function fetch_interval_quantifier (formerly known as fetch_range_quantifier) in regparse.c, PFETCH is called without checking PEND. This leads to a heap-based buffer over-read.
https://github.com/kkos/oniguruma/issues/162
https://github.com/kkos/oniguruma/releases/tag/v6.9.4_rc2
https://github.com/ManhNDd/CVE-2019-19204
https://github.com/tarantula-team/CVE-2019-19204
https://lists.debian.org/debian-lts-announce/2019/12/msg00002.html
Source: MITRE
Published: 2019-11-21
Updated: 2020-08-24
Type: CWE-125
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH