In the flush_tmregs_to_thread function in arch/powerpc/kernel/ptrace.c in the Linux kernel before 4.13.5, a guest kernel crash can be triggered from unprivileged userspace during a core dump on a POWER host due to a missing processor feature check and an erroneous use of transactional memory (TM) instructions in the core dump path, leading to a denial of service.
http://openwall.com/lists/oss-security/2018/03/27/4
https://access.redhat.com/errata/RHSA-2018:1318
https://access.redhat.com/security/cve/cve-2018-1091
https://bugzilla.redhat.com/show_bug.cgi?id=1558149
https://github.com/torvalds/linux/commit/c1fa0768a8713b135848f78fd43ffc208d8ded70
https://marc.info/?l=linuxppc-embedded&m=150535531910494&w=2
https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.5
Source: MITRE
Published: 2018-03-27
Updated: 2018-05-10
Type: CWE-119
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:3.0/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