CVE-2019-15791 - CVE House
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Status published High CVE-2019-15791

Reference count underflow in shiftfs

Vulnerability Description

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, shiftfs_btrfs_ioctl_fd_replace() installs an fd referencing a file from the lower filesystem without taking an additional reference to that file. After the btrfs ioctl completes this fd is closed, which then puts a reference to that file, leading to a refcount underflow.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Jann Horn of Google Project Zero

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Affected Vendor

Affected Software

Shiftfs in the Linux kernel
Vulnerable Versions:
5.3.0-11.12, 5.0 kernel

Timeline

Official Publish: April 23rd, 2020
Last Modified: September 17th, 2024
Added to House: July 20th, 2026

CVSS Vectors

V3: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Weaknesses (CWE)

CWE-672

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.