CVE-2021-3489 Information

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 (pf 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 (pf: Implement BPF ring buffer and verifier support for it) (v5.8-rc1).

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

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 https://www.openwall.com/lists/oss-security/2021/05/11/10 https://security.netapp.com/advisory/ntap-20210716-0004/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8