CVE-2019-15794

What it is

Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data tampering, service disruption.

Exploit odds

1.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-04-24 00:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 02:21 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.2% in the next 30 days (EPSS).
• Severity: 7.1 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-04-24 00:15 UTC

Last modified

2026-06-17 02:21 UTC

Exploit probability

1.2% · EPSS, next 30 days

Weakness

CWE-672

Record status

Modified

Affected

• Linux Kernel 5.0
• Linux Kernel 5.3
• Canonical Ubuntu Linux 18.04
• Canonical Ubuntu Linux 19.10

Attack profile CVSS 3.1 · 7.1

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2019-15794.md and follow it. Check whether this project is affected by CVE-2019-15794. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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