TI-2019-11862 Aliases CVE-2019-15791 GHSA-5fx5-7qgj-cmg7

Reference count underflow in shiftfs

LOW 37CWE-672Published 2020-04-23 · Updated 2024-09-17

Key facts

Attack vector: Local
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-191 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.01317 70th percentileScored 2026-11-07

Fix Fixed Shiftfs in the Linux kernel (Ubuntu): 5.0.0-35.38

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Ubuntu	Shiftfs in the Linux kernel	5.3.0-11.12 and later; 5.0 kernel to before 5.0.0-35.38	5.0.0-35.38	Patch available	CNA

Shiftfs in the Linux kernel VendorUbuntu Affected 5.3.0-11.12 and later; 5.0 kernel to before 5.0.0-35.38 Fixed in 5.0.0-35.38 Patch available CNA

CPE configurations NVD · 4

CPE	Versions	Role	Vendor
cpe:2.3:o:linux:linux_kernel:5.0:::::::*	5.0	Vulnerable	Linux
cpe:2.3:o:linux:linux_kernel:5.3:::::::*	5.3	Vulnerable	Linux
cpe:2.3:o:canonical:ubuntu_linux:18.04::::lts:::	18.04	Vulnerable	Canonical
cpe:2.3:o:canonical:ubuntu_linux:19.04:::::::*	19.04	Vulnerable	Canonical

cpe:2.3:o:linux:linux_kernel:5.0:*:*:*:*:*:*:* Versions 5.0 Vulnerable ·Linux
cpe:2.3:o:linux:linux_kernel:5.3:*:*:*:*:*:*:* Versions 5.3 Vulnerable ·Linux
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:* Versions 19.04 Vulnerable ·Canonical

Remediation

Fix · CNA Shiftfs in the Linux kernel (Ubuntu) Fixed in 5.0.0-35.38

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2020-04-23
Ubuntu Shiftfs in the Linux kernel 5.0.0-35.38, 5.3 kernel*
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2019-11864 Mishandling of file-system uid/gid with namespaces in shiftfsPriority LOW 39
- TI-2019-11863 Type confusion in shiftfsPriority LOW 36
Show all 3 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 5 products

Red Hat Enterprise Linux 5
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8
Red Hat Enterprise MRG 2

Timeline

2026-10-02 Threatist record created from CVE-2019-15791
2026-10-03 Alias added: GHSA-5fx5-7qgj-cmg7

References

Patch 1

https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=601a64857b3d7040ca15c39c929e6b9db3373ec1

Advisory 2

TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
TI-2007-05153 Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD… CVSS 2.0HIGH 7.2
TI-2004-01032 Multiple vulnerabilities in the IGMP functionality for Linux kernel 2.4.22 to 2.4.28, and… CVSS 2.0HIGH 10.0
TI-2004-00896 Multiple buffer overflows in libXML 2.6.12 and 2.6.13 (libxml2), and possibly other… CVSS 2.0HIGH 10.0
TI-2004-00800 Buffer overflow in the QFILEPATHINFO request handler in Samba 3.0.x through 3.0.7 may… CVSS 2.0HIGH 10.0
TI-2004-00962 Buffer overflow in the exif_read_data function in PHP before 4.3.10 and PHP 5.x up to… CVSS 2.0HIGH 10.0

See all 129 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences