rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 certificates from a peer that can result in Remote code execution. This attack appear to be exploitable a remote attacker that can connect to rsyslog and trigger a stack buffer overflow by sending a specially crafted x509 certificate.
https://access.redhat.com/errata/RHSA-2018:1223
https://access.redhat.com/errata/RHSA-2018:1225
https://access.redhat.com/errata/RHSA-2018:1701
https://access.redhat.com/errata/RHSA-2018:1702
https://access.redhat.com/errata/RHSA-2018:1703
https://access.redhat.com/errata/RHSA-2018:1704
https://access.redhat.com/errata/RHSA-2018:1707
https://github.com/rsyslog/librelp/blob/532aa362f0f7a8d037505b0a27a1df452f9bac9e/src/tcp.c#L1205
https://lgtm.com/rules/1505913226124/
https://security.gentoo.org/glsa/201804-21
Source: MITRE
Published: 2018-03-23
Updated: 2020-08-24
Type: CWE-787
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