Vulnerabilities
Misconfiguration
Compliance
CVE Vulnerabilities

CVE-2021-3493

Privilege Context Switching Error

Published: Apr 17, 2021 | Modified: Oct 28, 2025
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
7.4 MODERATE
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Ubuntu
HIGH
Vulnerability-free packages from our partners
root.io logo minimus.io logo echo.ai logo
Additional information
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2021-3493
CWEhttps://cwe.mitre.org/data/definitions/270.html

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 unprivileged overlay mounts, an attacker could use this to gain elevated privileges.

Weakness

The product does not properly manage privileges while it is switching between different contexts that have different privileges or spheres of control.

Affected Software

NameVendorStart VersionEnd Version
Ubuntu_linuxCanonical*18.04 (excluding)
Ubuntu_linuxCanonical18.04.1 (including)20.04 (excluding)
LinuxUbuntubionic*
LinuxUbuntuesm-infra/bionic*
LinuxUbuntuesm-infra/focal*
LinuxUbuntuesm-infra/xenial*
LinuxUbuntufocal*
LinuxUbuntugroovy*
LinuxUbuntuprecise/esm*
LinuxUbuntuupstream*
LinuxUbuntuxenial*
Linux-allwinnerUbuntuupstream*
Linux-allwinner-5.19Ubuntuupstream*
Linux-awsUbuntubionic*
Linux-awsUbuntuesm-infra-legacy/trusty*
Linux-awsUbuntuesm-infra/bionic*
Linux-awsUbuntuesm-infra/focal*
Linux-awsUbuntuesm-infra/xenial*
Linux-awsUbuntufocal*
Linux-awsUbuntugroovy*
Linux-awsUbuntutrusty*
Linux-awsUbuntutrusty/esm*
Linux-awsUbuntuupstream*
Linux-awsUbuntuxenial*
Linux-aws-5.0Ubuntubionic*
Linux-aws-5.0Ubuntuesm-infra/bionic*
Linux-aws-5.0Ubuntuupstream*
Linux-aws-5.11Ubuntuupstream*
Linux-aws-5.13Ubuntuupstream*
Linux-aws-5.15Ubuntuupstream*
Linux-aws-5.19Ubuntuupstream*
Linux-aws-5.3Ubuntubionic*
Linux-aws-5.3Ubuntuesm-infra/bionic*
Linux-aws-5.3Ubuntuupstream*
Linux-aws-5.4Ubuntubionic*
Linux-aws-5.4Ubuntuesm-infra/bionic*
Linux-aws-5.4Ubuntuupstream*
Linux-aws-5.8Ubuntuupstream*
Linux-aws-6.14Ubuntuupstream*
Linux-aws-6.2Ubuntuupstream*
Linux-aws-6.5Ubuntuupstream*
Linux-aws-6.8Ubuntuupstream*
Linux-aws-fipsUbuntufips-updates/bionic*
Linux-aws-fipsUbuntufips-updates/focal*
Linux-aws-fipsUbuntufips/bionic*
Linux-aws-fipsUbuntufips/focal*
Linux-aws-fipsUbuntutrusty*
Linux-aws-fipsUbuntuupstream*
Linux-aws-fipsUbuntuxenial*
Linux-aws-hweUbuntuesm-infra/xenial*
Linux-aws-hweUbuntuupstream*
Linux-aws-hweUbuntuxenial*
Linux-azureUbuntubionic*
Linux-azureUbuntuesm-infra-legacy/trusty*
Linux-azureUbuntuesm-infra/bionic*
Linux-azureUbuntuesm-infra/focal*
Linux-azureUbuntuesm-infra/xenial*
Linux-azureUbuntufocal*
Linux-azureUbuntugroovy*
Linux-azureUbuntutrusty*
Linux-azureUbuntutrusty/esm*
Linux-azureUbuntuupstream*
Linux-azureUbuntuxenial*
Linux-azure-4.15Ubuntubionic*
Linux-azure-4.15Ubuntuesm-infra/bionic*
Linux-azure-4.15Ubuntuupstream*
Linux-azure-5.11Ubuntuupstream*
Linux-azure-5.13Ubuntuupstream*
Linux-azure-5.15Ubuntuupstream*
Linux-azure-5.19Ubuntuupstream*
Linux-azure-5.3Ubuntubionic*
Linux-azure-5.3Ubuntuesm-infra/bionic*
Linux-azure-5.3Ubuntuupstream*
Linux-azure-5.4Ubuntubionic*
Linux-azure-5.4Ubuntuesm-infra/bionic*
Linux-azure-5.4Ubuntuupstream*
Linux-azure-5.8Ubuntuupstream*
Linux-azure-6.11Ubuntuupstream*
Linux-azure-6.14Ubuntuupstream*
Linux-azure-6.2Ubuntuupstream*
Linux-azure-6.5Ubuntuupstream*
Linux-azure-6.8Ubuntuupstream*
Linux-azure-edgeUbuntubionic*
Linux-azure-edgeUbuntuesm-infra/bionic*
Linux-azure-edgeUbuntuupstream*
Linux-azure-fdeUbuntuesm-infra/focal*
Linux-azure-fdeUbuntufocal*
Linux-azure-fdeUbuntuupstream*
Linux-azure-fde-5.15Ubuntuupstream*
Linux-azure-fde-5.19Ubuntuupstream*
Linux-azure-fde-6.14Ubuntuupstream*
Linux-azure-fde-6.2Ubuntuupstream*
Linux-azure-fde-6.8Ubuntuupstream*
Linux-azure-fipsUbuntufips-updates/bionic*
Linux-azure-fipsUbuntufips-updates/focal*
Linux-azure-fipsUbuntufips/bionic*
Linux-azure-fipsUbuntufips/focal*
Linux-azure-fipsUbuntutrusty*
Linux-azure-fipsUbuntuupstream*
Linux-azure-fipsUbuntuxenial*
Linux-azure-nvidiaUbuntuupstream*
Linux-azure-nvidia-6.14Ubuntuupstream*
Linux-bluefieldUbuntuupstream*
Linux-dell300xUbuntubionic*
Linux-dell300xUbuntuupstream*
Linux-fipsUbuntufips-updates/bionic*
Linux-fipsUbuntufips-updates/xenial*
Linux-fipsUbuntufips/bionic*
Linux-fipsUbuntufips/focal*
Linux-fipsUbuntufips/xenial*
Linux-fipsUbuntuupstream*
Linux-gcpUbuntubionic*
Linux-gcpUbuntuesm-infra/bionic*
Linux-gcpUbuntuesm-infra/focal*
Linux-gcpUbuntuesm-infra/xenial*
Linux-gcpUbuntufocal*
Linux-gcpUbuntugroovy*
Linux-gcpUbuntuupstream*
Linux-gcpUbuntuxenial*
Linux-gcp-4.15Ubuntubionic*
Linux-gcp-4.15Ubuntuesm-infra/bionic*
Linux-gcp-4.15Ubuntuupstream*
Linux-gcp-5.11Ubuntuupstream*
Linux-gcp-5.13Ubuntuupstream*
Linux-gcp-5.15Ubuntuupstream*
Linux-gcp-5.19Ubuntuupstream*
Linux-gcp-5.3Ubuntubionic*
Linux-gcp-5.3Ubuntuesm-infra/bionic*
Linux-gcp-5.3Ubuntuupstream*
Linux-gcp-5.4Ubuntubionic*
Linux-gcp-5.4Ubuntuesm-infra/bionic*
Linux-gcp-5.4Ubuntuupstream*
Linux-gcp-5.8Ubuntuupstream*
Linux-gcp-6.11Ubuntuupstream*
Linux-gcp-6.14Ubuntuupstream*
Linux-gcp-6.2Ubuntuupstream*
Linux-gcp-6.5Ubuntuupstream*
Linux-gcp-6.8Ubuntuupstream*
Linux-gcp-edgeUbuntubionic*
Linux-gcp-edgeUbuntuesm-infra/bionic*
Linux-gcp-edgeUbuntuupstream*
Linux-gcp-fipsUbuntufips-updates/focal*
Linux-gcp-fipsUbuntufips/bionic*
Linux-gcp-fipsUbuntufips/focal*
Linux-gcp-fipsUbuntutrusty*
Linux-gcp-fipsUbuntuupstream*
Linux-gcp-fipsUbuntuxenial*
Linux-gkeUbuntuesm-infra/focal*
Linux-gkeUbuntufocal*
Linux-gkeUbuntuupstream*
Linux-gkeUbuntuxenial*
Linux-gke-4.15Ubuntubionic*
Linux-gke-4.15Ubuntuesm-infra/bionic*
Linux-gke-4.15Ubuntuupstream*
Linux-gke-5.0Ubuntubionic*
Linux-gke-5.0Ubuntuupstream*
Linux-gke-5.15Ubuntuupstream*
Linux-gke-5.3Ubuntubionic*
Linux-gke-5.3Ubuntuupstream*
Linux-gke-5.4Ubuntubionic*
Linux-gke-5.4Ubuntuesm-infra/bionic*
Linux-gke-5.4Ubuntuupstream*
Linux-gkeopUbuntuesm-infra/focal*
Linux-gkeopUbuntufocal*
Linux-gkeopUbuntuupstream*
Linux-gkeop-5.15Ubuntuupstream*
Linux-gkeop-5.4Ubuntubionic*
Linux-gkeop-5.4Ubuntuesm-infra/bionic*
Linux-gkeop-5.4Ubuntuupstream*
Linux-hweUbuntubionic*
Linux-hweUbuntuesm-infra/bionic*
Linux-hweUbuntuesm-infra/xenial*
Linux-hweUbuntuupstream*
Linux-hweUbuntuxenial*
Linux-hwe-5.11Ubuntuupstream*
Linux-hwe-5.13Ubuntuupstream*
Linux-hwe-5.15Ubuntuupstream*
Linux-hwe-5.19Ubuntuupstream*
Linux-hwe-5.4Ubuntubionic*
Linux-hwe-5.4Ubuntuesm-infra/bionic*
Linux-hwe-5.4Ubuntuupstream*
Linux-hwe-5.8Ubuntuesm-infra/focal*
Linux-hwe-5.8Ubuntufocal*
Linux-hwe-5.8Ubuntuupstream*
Linux-hwe-6.11Ubuntuupstream*
Linux-hwe-6.14Ubuntuupstream*
Linux-hwe-6.2Ubuntuupstream*
Linux-hwe-6.5Ubuntuupstream*
Linux-hwe-6.8Ubuntuupstream*
Linux-hwe-edgeUbuntubionic*
Linux-hwe-edgeUbuntuesm-infra/bionic*
Linux-hwe-edgeUbuntuesm-infra/xenial*
Linux-hwe-edgeUbuntuupstream*
Linux-hwe-edgeUbuntuxenial*
Linux-ibmUbuntuupstream*
Linux-ibm-5.15Ubuntuupstream*
Linux-ibm-5.4Ubuntuupstream*
Linux-ibm-6.8Ubuntuupstream*
Linux-intelUbuntuupstream*
Linux-intel-5.13Ubuntuupstream*
Linux-intel-iot-realtimeUbuntujammy*
Linux-intel-iot-realtimeUbuntuupstream*
Linux-intel-iotgUbuntuupstream*
Linux-intel-iotg-5.15Ubuntuupstream*
Linux-iotUbuntuupstream*
Linux-kvmUbuntubionic*
Linux-kvmUbuntuesm-infra/bionic*
Linux-kvmUbuntuesm-infra/focal*
Linux-kvmUbuntuesm-infra/xenial*
Linux-kvmUbuntufocal*
Linux-kvmUbuntugroovy*
Linux-kvmUbuntuupstream*
Linux-kvmUbuntuxenial*
Linux-laptopUbuntuupstream*
Linux-lowlatencyUbuntuupstream*
Linux-lowlatency-hwe-5.15Ubuntuupstream*
Linux-lowlatency-hwe-5.19Ubuntuupstream*
Linux-lowlatency-hwe-6.11Ubuntuupstream*
Linux-lowlatency-hwe-6.2Ubuntuupstream*
Linux-lowlatency-hwe-6.5Ubuntuupstream*
Linux-lowlatency-hwe-6.8Ubuntuupstream*
Linux-lts-trustyUbuntuprecise/esm*
Linux-lts-trustyUbuntuupstream*
Linux-lts-xenialUbuntuesm-infra-legacy/trusty*
Linux-lts-xenialUbuntutrusty*
Linux-lts-xenialUbuntutrusty/esm*
Linux-lts-xenialUbuntuupstream*
Linux-nvidiaUbuntuupstream*
Linux-nvidia-6.11Ubuntuupstream*
Linux-nvidia-6.2Ubuntuupstream*
Linux-nvidia-6.5Ubuntuupstream*
Linux-nvidia-6.8Ubuntuupstream*
Linux-nvidia-lowlatencyUbuntuupstream*
Linux-nvidia-tegraUbuntuupstream*
Linux-nvidia-tegra-5.15Ubuntuupstream*
Linux-nvidia-tegra-igxUbuntuupstream*
Linux-oemUbuntubionic*
Linux-oemUbuntuesm-infra/bionic*
Linux-oemUbuntuupstream*
Linux-oemUbuntuxenial*
Linux-oem-5.10Ubuntuesm-infra/focal*
Linux-oem-5.10Ubuntufocal*
Linux-oem-5.10Ubuntuupstream*
Linux-oem-5.13Ubuntuupstream*
Linux-oem-5.14Ubuntuupstream*
Linux-oem-5.17Ubuntuupstream*
Linux-oem-5.6Ubuntuesm-infra/focal*
Linux-oem-5.6Ubuntufocal*
Linux-oem-5.6Ubuntuupstream*
Linux-oem-6.0Ubuntuupstream*
Linux-oem-6.1Ubuntuupstream*
Linux-oem-6.11Ubuntuupstream*
Linux-oem-6.14Ubuntuupstream*
Linux-oem-6.17Ubuntuupstream*
Linux-oem-6.5Ubuntuupstream*
Linux-oem-6.8Ubuntuupstream*
Linux-oem-osp1Ubuntubionic*
Linux-oem-osp1Ubuntuupstream*
Linux-oracleUbuntubionic*
Linux-oracleUbuntuesm-infra/bionic*
Linux-oracleUbuntuesm-infra/focal*
Linux-oracleUbuntuesm-infra/xenial*
Linux-oracleUbuntufocal*
Linux-oracleUbuntugroovy*
Linux-oracleUbuntuupstream*
Linux-oracleUbuntuxenial*
Linux-oracle-5.0Ubuntubionic*
Linux-oracle-5.0Ubuntuesm-infra/bionic*
Linux-oracle-5.0Ubuntuupstream*
Linux-oracle-5.11Ubuntuupstream*
Linux-oracle-5.13Ubuntuupstream*
Linux-oracle-5.15Ubuntuupstream*
Linux-oracle-5.3Ubuntubionic*
Linux-oracle-5.3Ubuntuesm-infra/bionic*
Linux-oracle-5.3Ubuntuupstream*
Linux-oracle-5.4Ubuntubionic*
Linux-oracle-5.4Ubuntuesm-infra/bionic*
Linux-oracle-5.4Ubuntuupstream*
Linux-oracle-5.8Ubuntuupstream*
Linux-oracle-6.14Ubuntuupstream*
Linux-oracle-6.5Ubuntuupstream*
Linux-oracle-6.8Ubuntuupstream*
Linux-raspiUbuntuesm-infra/focal*
Linux-raspiUbuntufocal*
Linux-raspiUbuntugroovy*
Linux-raspiUbuntuupstream*
Linux-raspi-5.4Ubuntubionic*
Linux-raspi-5.4Ubuntuesm-infra/bionic*
Linux-raspi-5.4Ubuntuupstream*
Linux-raspi-realtimeUbuntunoble*
Linux-raspi-realtimeUbuntuupstream*
Linux-raspi2Ubuntubionic*
Linux-raspi2Ubuntuesm-infra/focal*
Linux-raspi2Ubuntufocal*
Linux-raspi2Ubuntuupstream*
Linux-raspi2Ubuntuxenial*
Linux-raspi2-5.3Ubuntubionic*
Linux-raspi2-5.3Ubuntuupstream*
Linux-realtimeUbuntujammy*
Linux-realtimeUbuntuupstream*
Linux-realtime-6.14Ubuntuupstream*
Linux-realtime-6.8Ubuntuupstream*
Linux-riscvUbuntuesm-infra/focal*
Linux-riscvUbuntufocal*
Linux-riscvUbuntugroovy*
Linux-riscvUbuntuupstream*
Linux-riscv-5.11Ubuntuupstream*
Linux-riscv-5.15Ubuntuupstream*
Linux-riscv-5.19Ubuntuupstream*
Linux-riscv-5.8Ubuntuesm-infra/focal*
Linux-riscv-5.8Ubuntufocal*
Linux-riscv-5.8Ubuntuupstream*
Linux-riscv-6.14Ubuntuupstream*
Linux-riscv-6.5Ubuntuupstream*
Linux-riscv-6.8Ubuntuupstream*
Linux-snapdragonUbuntubionic*
Linux-snapdragonUbuntuupstream*
Linux-snapdragonUbuntuxenial*
Linux-starfiveUbuntuupstream*
Linux-starfive-5.19Ubuntuupstream*
Linux-starfive-6.2Ubuntuupstream*
Linux-starfive-6.5Ubuntuupstream*
Linux-xilinxUbuntuupstream*
Linux-xilinx-zynqmpUbuntuupstream*

Potential Mitigations

References

Aqua Security is the largest pure-play cloud native security company, providing customers the freedom to innovate and run their businesses with minimal friction. The Aqua Cloud Native Security Platform provides prevention, detection, and response automation across the entire application lifecycle to secure the build, secure cloud infrastructure and secure running workloads wherever they are deployed.
Copyright © 2026 Aqua Security Software Ltd.   Privacy Policy | Terms of Use