The coredump implementation in the Linux kernel before 5.0.10 does not use locking or other mechanisms to prevent vma layout or vma flags changes while it runs, which allows local users to obtain sensitive information, cause a denial of service, or possibly have unspecified other impact by triggering a race condition with mmget_not_zero or get_task_mm calls. This is related to fs/userfaultfd.c, mm/mmap.c, fs/proc/task_mmu.c, and drivers/infiniband/core/uverbs_main.c.
https://www.oracle.com/security-alerts/cpuApr2021.html
https://www.exploit-db.com/exploits/46781/
https://www.debian.org/security/2019/dsa-4465
https://usn.ubuntu.com/4118-1/
https://usn.ubuntu.com/4115-1/
https://usn.ubuntu.com/4095-1/
https://usn.ubuntu.com/4069-2/
https://usn.ubuntu.com/4069-1/
https://support.f5.com/csp/article/K51674118?utm_source=f5support&%3Butm_medium=RSS
https://support.f5.com/csp/article/K51674118
https://security.netapp.com/advisory/ntap-20200608-0001/
https://security.netapp.com/advisory/ntap-20190517-0002/
https://seclists.org/bugtraq/2019/Jun/26
https://seclists.org/bugtraq/2019/Jul/33
https://lists.debian.org/debian-lts-announce/2019/06/msg00011.html
https://lists.debian.org/debian-lts-announce/2019/05/msg00042.html
https://lists.debian.org/debian-lts-announce/2019/05/msg00041.html
https://github.com/torvalds/linux/commit/04f5866e41fb70690e28397487d8bd8eea7d712a
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.10
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.37
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.114
https://bugs.chromium.org/p/project-zero/issues/detail?id=1790
https://access.redhat.com/errata/RHSA-2020:0543
https://access.redhat.com/errata/RHSA-2020:0179
https://access.redhat.com/errata/RHSA-2020:0103
https://access.redhat.com/errata/RHSA-2020:0100
https://access.redhat.com/errata/RHSA-2019:3517
https://access.redhat.com/errata/RHSA-2019:3309
https://access.redhat.com/errata/RHSA-2019:2043
https://access.redhat.com/errata/RHSA-2019:2029
http://www.securityfocus.com/bid/108113
http://www.openwall.com/lists/oss-security/2019/04/30/1
http://www.openwall.com/lists/oss-security/2019/04/29/2
http://www.openwall.com/lists/oss-security/2019/04/29/1
http://packetstormsecurity.com/files/152663/Linux-Missing-Lockdown.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00025.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00014.html