HIGH
In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to create a ptrace relationship, which allows local users to obtain root access by leveraging certain scenarios with a parent-child process relationship, where a parent drops privileges and calls execve (potentially allowing control by an attacker). One contributing factor is an object lifetime issue (which can also cause a panic). Another contributing factor is incorrect marking of a ptrace relationship as privileged, which is exploitable through (for example) Polkit's pkexec helper with PTRACE_TRACEME. NOTE: SELinux deny_ptrace might be a usable workaround in some environments.
http://packetstormsecurity.com/files/154245/Kernel-Live-Patch-Security-Notice-LSN-0054-1.html
https://access.redhat.com/errata/RHSA-2019:2405
https://access.redhat.com/errata/RHSA-2019:2411
https://bugs.chromium.org/p/project-zero/issues/detail?id=1903
https://bugzilla.redhat.com/show_bug.cgi?id=1730895
https://bugzilla.suse.com/show_bug.cgi?id=1140671
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.1.17
https://github.com/torvalds/linux/commit/6994eefb0053799d2e07cd140df6c2ea106c41ee
https://lists.debian.org/debian-lts-announce/2019/07/msg00022.html
https://lists.debian.org/debian-lts-announce/2019/07/msg00023.html
https://seclists.org/bugtraq/2019/Jul/30
https://seclists.org/bugtraq/2019/Jul/33
https://security.netapp.com/advisory/ntap-20190806-0001/
https://support.f5.com/csp/article/K91025336
https://usn.ubuntu.com/4093-1/
https://usn.ubuntu.com/4094-1/
https://usn.ubuntu.com/4095-1/
https://usn.ubuntu.com/4117-1/
Source: MITRE
Published: 2019-07-17
Updated: 2019-07-25
Type: CWE-264
Base Score: 7.2
Vector: AV:L/AC:L/Au:N/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 3.9
Severity: HIGH
Base Score: 7.8
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.8
Severity: HIGH