CVE-2021-3490

Linux Kernel vulnerability

CVSS

7.8

EPSS

27.5%

EPSS pct

98th

Exploited

No known

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).

Affected vendor

Linux

Affected product

Linux Kernel

CVSS vector

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

Weakness type (CWE)

CWE-20 — Improper Input Validation
CWE-787 — Out-of-bounds Write
CWE-125 — Out-of-bounds Read

Published

2021-06-04

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable with local access, high attack complexity, requiring low privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 27.5% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 98% of all scored CVEs.

Check your external exposure to CVE-2021-3490

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How ThreatPort helps with CVE-2021-3490

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