CVE-2020-16120 — Incorrect Privilege Assignment in Kernel

CWE-266 — Incorrect Privilege AssignmentCWE-269 — Improper Privilege ManagementCWE-1220 — Insufficient Granularity of Access Control13 documents9 sources
Severity
4.4MEDIUMNVD
CNA5.1
EPSS
0.0%
top 85.64%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Linux KernelLinux KernelCanonical Ubuntu Linux
Timeline
PublishedFeb 10
Latest updateMay 24

Description

Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef ("ovl: stack file ops"). This was fixed in kernel version 5.8 by commits 56230d9 ("ovl:…

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:NExploitability: 0.8 | Impact: 3.6

Affected Packages3 packages

▶NVDlinux/linux_kernel< 5.11
▶CVEListV5linux_kernel/linux_kernel5.11-stable — 5.11.0
▶Debianlinux/linux_kernel< 5.8.7-1+3

Also affects: Ubuntu Linux 14.04, 16.04, 18.04, 20.04

Patches

Patch: git.kernel.org ↗Patch: git.kernel.org ↗Patch: git.kernel.org ↗

🔴Vulnerability Details

4
GHSA
GHSA-q6jw-34cj-733v: Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if,↗2022-05-24
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OSV
CVE-2020-16120: Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if,↗2021-02-10
▶
CVEList
Unprivileged overlay + shiftfs read access↗2021-02-10
▶
OSV
linux-hwe, linux-gke-5.0, linux-gke-5.3, linux-oem-osp1, linux-raspi2-5.3 vulnerabilities↗2020-10-14
▶

📋Vendor Advisories

7
Microsoft
Unprivileged overlay + shiftfs read access↗2021-02-09
▶
Ubuntu
Linux kernel vulnerabilities↗2020-10-14
▶
Ubuntu
Linux kernel vulnerabilities↗2020-10-14
▶
Ubuntu
Linux kernel vulnerabilities↗2020-10-14
▶
Ubuntu
Kernel Live Patch Security Notice↗2020-10-14
▶

💬Community

1
Bugzilla
CVE-2020-16120 kernel: incorrect unprivileged overlayfs permission checking may lead to information disclosure↗2020-10-08
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CVE-2020-16120 — Incorrect Privilege Assignment | cvebase