CVE-2021-3489

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).

Related CPE's

References

https://www.zerodayinitiative.com/advisories/ZDI-21-590/

https://ubuntu.com/security/notices/USN-4949-1

https://ubuntu.com/security/notices/USN-4950-1

https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6ea

[oss-security] CVE-2021-3489 - Linux kernel eBPF RINGBUF map oversized allocation

CvssV3 impact

CvssV2 impact