CVE-2021-3490CWE-20CWE-787

Linux kernel eBPF bitwise ops ALU32 bounds tracking

High · published June 4, 2021

CVSS v3.1
7.8
EPSS
27%
Percentile
98.1
In the wild
Unconfirmed
What it is

The eBPF ALU32 bounds tracking for bitwise ops (AND, OR and XOR) in the Linux kernel did not properly update 32-bit bounds, which could be turned into out of bounds reads and writes in the Linux kernel and therefore, arbitrary code execution. This issue was fixed via commit 049c4e13714e ("bpf: Fix alu32 const subreg bound tracking on bitwise operations") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. The AND/OR issues were introduced by commit 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking") (5.7-rc1) and the XOR variant was introduced by 2921c90d4718 ("bpf:Fix a verifier failure with xor") ( 5.10-rc1).

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.27179 · 98.1th percentile
Weaknesses
CWE-20 · Improper Input Validation; CWE-787 · Out-of-bounds Write
Published
2021-06-04T01:40Z
EPSS history
Timeline
  • 04 JUN 01:40Z
    Linux kernel eBPF bitwise ops ALU32 bounds tracking
    cvelistv5