CVE-2019-15793 - CVE House
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Status published Medium CVE-2019-15793

Mishandling of file-system uid/gid with namespaces 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, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. A local attacker could use this to possibly bypass discretionary access control permissions.

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 16th, 2024
Added to House: July 20th, 2026

CVSS Vectors

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

Weaknesses (CWE)

CWE-538

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.