SB2021032929 - Ubuntu update for linux

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Observable discrepancy (CVE-ID: CVE-2020-27170)

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists in kernel/bpf/verifier.c due to kernel performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations. A local user can run a specially crafted program to gain access to sensitive information.

2) Off-by-one (CVE-ID: CVE-2020-27171)

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to an off-by-one error in kernel/bpf/verifier.c affecting out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations. A local user can run a specially crafted program to gain access to sensitive information on the system.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-4890-1