CVE-2020-8835 Linux kernel bpf verifier vulnerability

What is CVE-2020-8835?

CVE-2020-8835 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 2 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel 5.5.0 and newer, the bpf verifier (kernel/bpf/verifier.c) did not properly restrict the register bounds for 32-bit operations, leading to out-of-bounds reads and writes in kernel memory. The vulnerability also affects the Linux 5.4 stable series, starting with v5.4.7, as the introducing commit was backported to that branch. This vulnerability was fixed in 5.6.1, 5.5.14, and 5.4.29. (issue is aka ZDI-CAN-10780)

Weakness: CWE-787, CWE-125

Which versions are affected by CVE-2020-8835?

It affects 27 products.

Products include Canonical Ubuntu Linux, Fedoraproject Fedora, Linux kernel, Netapp 8300 Firmware, Netapp 8700 Firmware, Netapp A220 Firmware and 21 more.

How do I fix CVE-2020-8835?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2020-8835 being exploited?

There is no known exploitation of CVE-2020-8835 in the wild and no public exploit code.

Public exploit code: 7 proofs of concept on GitHub.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2020-8835, GHSA-774r-wvx9-mm68, UBUNTU-CVE-2020-8835, USN-4313-1.