CVE-2021-3489 Linux kernel eBPF RINGBUF map oversized allocation

What is CVE-2021-3489?

CVE-2021-3489 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 4 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee ("bpf, ringbuf: Deny reserve of buffers larger than ringbuf") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced via 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") (v5.8-rc1).

Weakness: CWE-787, CWE-119

Which versions are affected by CVE-2021-3489?

It affects 2 products.

Products include Canonical Ubuntu Linux, Linux kernel.

How do I fix CVE-2021-3489?

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-2021-3489 being exploited?

There is no known exploitation of CVE-2021-3489 in the wild and no public exploit code.

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 A-190877279, DEBIAN-CVE-2021-3489, GHSA-45wv-rq2g-2vvj, PUB-A-190877279, UBUNTU-CVE-2021-3489.