Privilege Escalation

Bubblewrap bwrap is vulnerable to privilege escalation. If installed in setuid mode and the kernel supports unprivileged user namespaces, then the bwrap --userns2 option can be used to make the setuid process keep running as root while being traceable. This can in turn be used to gain root...

USN-4916-2 linux, linux-aws, linux-gke-5.3, linux-hwe, linux-kvm, linux-lts-xenial, linux-oem-5.6, linux-raspi2, linux-raspi2-5.3, linux-snapdragon regression

USN-4916-1 fixed vulnerabilities in the Linux kernel. Unfortunately, the fix for CVE-2021-3493 introduced a memory leak in some situations. This update fixes the problem. We apologize for the inconvenience. Original advisory details: It was discovered that the overlayfs implementation in the Linu...

Ubuntu: Security Advisory (USN-4916-2)

The remote host is missing an update for the SPDX-FileCopyrightText: 2021 Greenbone AG Some text descriptions might be excerpted from a referenced sources, and are Copyright C by the respective right holders. SPDX-License-Identifier: GPL-2.0-only ifdescription...

Linux kernel elevation of privilege vulnerability (CNVD-2021-29853)

Linux kernel is the kernel used by Linux, the open source operating system of the Linux Foundation in the United States. A security vulnerability exists in the linux kernel that stems from a combination of unprivileged user namespaces and patches in the Ubuntu kernel that allow for unprivileged...

DEBIAN-CVE-2021-3493

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

CVE-2021-3493

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

Design/Logic Flaw

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

CVE-2021-3493

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

CVE-2021-3493

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

CVE-2021-3493

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

CVE-2021-3493

Summary: CVE-2021-3493 is a Linux kernel overlayfs privilege-escalation issue where overlayfs does not properly validate file capabilities against user namespaces, enabling local privilege escalation on systems using unprivileged user namespaces with Ubuntu overlay patches. The vulnerability is r...

CVE-2021-3493

A flaw was found in the Linux kernel. The overlayfs stacking file system does not properly validate the application of file capabilities against user namespaces. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability...

Ubuntu 16.04 LTS / 18.04 LTS : Linux kernel vulnerabilities (USN-4916-1)

The remote Ubuntu 16.04 LTS / 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4916-1 advisory. It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities...

Ubuntu: Security Advisory (USN-4917-1)

The remote host is missing an update for the SPDX-FileCopyrightText: 2021 Greenbone AG Some text descriptions might be excerpted from a referenced sources, and are Copyright C by the respective right holders. SPDX-License-Identifier: GPL-2.0-only ifdescription...

Ubuntu 20.04 LTS : Linux kernel (OEM) vulnerabilities (USN-4915-1)

The remote Ubuntu 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4915-1 advisory. It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respec...

USN-4917-1 linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gke-5.3, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe, linux-hwe-5.4, linux-hwe-5.8, linux-kvm, linux-oem-5.10, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4, linux-raspi2-5.3 vulnerabilities

It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. CVE-2021-3493 Vincent Dehors discovered that the shiftfs file...

USN-4916-1 linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-dell300x, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-lts-xenial, linux-oracle, linux-raspi2, linux-snapdragon vulnerabilities

It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. CVE-2021-3493 Piotr Krysiuk discovered that the BPF JIT...

USN-4915-1: Linux kernel (OEM) vulnerabilities

It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. CVE-2021-3493 Vincent Dehors discovered that the shiftfs file...

UBUNTU-CVE-2021-3493

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow...

DEBIAN-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, 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...