CVE-2021-3489

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Summary:

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).

Reference Links(if available):

  • 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
  • CVSS Score (if available)

    v2: / MEDIUMAV:L/AC:L/Au:N/C:C/I:C/A:C

    v3: / HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

    Links to Exploits(if available)

  • Available for Amazon Prime