An issue was discovered in sd-bus in systemd 239. bus_process_object() in libsystemd/sd-bus/bus-objects.c allocates a variable-length stack buffer for temporarily storing the object path of incoming D-Bus messages. An unprivileged local user can exploit this by sending a specially crafted message to PID1, causing the stack pointer to jump over the stack guard pages into an unmapped memory region and trigger a denial of service (systemd PID1 crash and kernel panic).
https://www.debian.org/security/2019/dsa-4393
https://usn.ubuntu.com/3891-1/
https://lists.debian.org/debian-lts-announce/2019/02/msg00031.html
https://github.com/systemd/systemd/commits/master/src/libsystemd/sd-bus/bus-objects.c
https://access.redhat.com/errata/RHSA-2019:0368
http://www.securityfocus.com/bid/107081
http://www.openwall.com/lists/oss-security/2019/02/19/1
http://www.openwall.com/lists/oss-security/2019/02/18/3
http://lists.opensuse.org/opensuse-security-announce/2019-02/msg00070.html
https://security.netapp.com/advisory/ntap-20190327-0004/
https://kc.mcafee.com/corporate/index?page=content&id=SB10278
https://access.redhat.com/errata/RHSA-2019:0990
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html
https://access.redhat.com/errata/RHSA-2019:1322
https://access.redhat.com/errata/RHSA-2019:1502
Source: MITRE
Published: 2019-03-21
Updated: 2022-02-20
Type: CWE-787
Base Score: 4.9
Vector: AV:L/AC:L/Au:N/C:N/I:N/A:C
Impact Score: 6.9
Exploitability Score: 3.9
Severity: MEDIUM
Base Score: 5.5
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 1.8
Severity: MEDIUM