CVE-2019-15794

Local code execution via mmap reference-count underflow

Published Apr 23, 2020 · Updated Sep 16, 2024

Reference-counting error in Ubuntu Linux Kernel 5.0 and 5.3 allows local users to crash the system or execute arbitrary code. The overlayfs and shiftfs mmap handlers replace vma->vm_file but fail to restore it after an error, and AUFS then calls vma_fput on the replacement, underflowing its reference count. Exploitation requires local access and the Ubuntu-specific AUFS interaction; upstream kernels without that caller do not dereference vm_file on the error path.

CVSS severity7.1
High
EPSS probability1.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference-counting error in Ubuntu Linux Kernel 5.0 and 5.3 allows local users to crash the system or execute arbitrary code. The overlayfs and shiftfs mmap handlers replace vma->vm_file but fail to restore it after an error, and AUFS then calls vma_fput on the replacement, underflowing its reference count. Exploitation requires local access and the Ubuntu-specific AUFS interaction; upstream kernels without that caller do not dereference vm_file on the error path.

The record

CVE
CVE-2019-15794
Published
Apr 23, 2020
Updated
Sep 16, 2024
Vendor
Linux Foundation
Product
Linux Kernel
Classifications
CWE-672, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 23, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.0 kernel <5.0.0-37.40
  2. Affected versionversion=5.3 kernel <5.3.0-24.26

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Linux Foundation · Linux Kernelversion=5.0 kernel <5.0.0-37.40; version=5.3 kernel <5.3.0-24.26

Published CVSS scores

6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
7.1Canonical Ltd.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-672Operation on a Resource after Expiration or Release
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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