Linux kernel regression

Releases

• Ubuntu 20.04 LTS
• Ubuntu 18.04 ESM
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

Packages

• linux - Linux kernel
• linux-aws - Linux kernel for Amazon Web Services (AWS) systems
• linux-gke-5.3 - Linux kernel for Google Container Engine (GKE) systems
• linux-hwe - Linux hardware enablement (HWE) kernel
• linux-kvm - Linux kernel for cloud environments
• linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty
• linux-oem-5.6 - Linux kernel for OEM systems
• linux-raspi2 - Linux kernel for Raspberry Pi (V8) systems
• linux-raspi2-5.3 - Linux kernel for Raspberry Pi (V8) systems
• linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

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 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 compiler for x86 in the Linux
kernel did not properly validate computation of branch displacements in
some situations. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2021-29154)