SB2021021033 - Security restrictions bypass in Linux kernel overlayfs
Published: February 10, 2021 Updated: May 12, 2025
Security Bulletin ID
SB2021021033
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Information disclosure
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Security restrictions bypass (CVE-ID: CVE-2020-16120)
CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls
CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local privileged user to gain access to sensitive information.
The vulnerability exists due to security restrictions bypass error within the ovl_open_realfile() and ovl_change_flags() functions in fs/overlayfs/file.c. A local privileged user can gain access to sensitive information.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/linus/b6650dab404c701d7fe08a108b746542a934da84
- https://launchpad.net/bugs/1894980
- https://ubuntu.com/USN-4578-1
- https://www.openwall.com/lists/oss-security/2020/10/14/2
- https://launchpad.net/bugs/1900141
- https://ubuntu.com/USN-4576-1
- https://git.kernel.org/linus/56230d956739b9cb1cbde439d76227d77979a04d
- https://git.kernel.org/linus/d1d04ef8572bc8c22265057bd3d5a79f223f8f52
- https://ubuntu.com/USN-4577-1
- https://git.kernel.org/linus/48bd024b8a40d73ad6b086de2615738da0c7004f
- https://git.kernel.org/linus/05acefb4872dae89e772729efb194af754c877e8
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.8