CVE-2021-3489

High

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).

SeverityHigh

CVSS7.8

Exploit probability—

Product

Linux Kernel

PublishedJun 4, 2021

First seenJun 4, 2021

Weakness typeCWE-119Memory buffer bounds error CWE-787Out-of-bounds write

How to fix

Update

linux linux_kernel5.10.37, 5.11.21, 5.12.4 or later

Vendor advisories

Affected products

Product	Affected versions	Fixed in
linux linux_kernel	5.8 ≤ v < 5.10.37, 5.11 ≤ v < 5.11.21, 5.12 ≤ v < 5.12.4, 5.13	5.10.37, 5.11.21, 5.12.4
canonical ubuntu_linux	20.04, 20.10, 21.04	—

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