CVE-2021-3444 Linux kernel bpf verifier incorrect mod32 truncation

2021-03-2300:00:00

CWE-681

canonical

www.cve.org

7.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

8.1 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.7%

JSON

The bpf verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker with the ability to load bpf programs could use this gain out-of-bounds reads in kernel memory leading to information disclosure (kernel memory), and possibly out-of-bounds writes that could potentially lead to code execution. This issue was addressed in the upstream kernel in commit 9b00f1b78809 (“bpf: Fix truncation handling for mod32 dst reg wrt zero”) and in Linux stable kernels 5.11.2, 5.10.19, and 5.4.101.

CNA Affected

[
  {
    "product": "kernel",
    "vendor": "Linux",
    "versions": [
      {
        "lessThan": "5.12-rc1",
        "status": "affected",
        "version": "trunk",
        "versionType": "custom"
      },
      {
        "lessThan": "5.11.2",
        "status": "affected",
        "version": "5.11",
        "versionType": "custom"
      },
      {
        "lessThan": "5.10.19",
        "status": "affected",
        "version": "5.10",
        "versionType": "custom"
      },
      {
        "lessThan": "5.4.101",
        "status": "affected",
        "version": "5.4",
        "versionType": "custom"
      }
    ]
  }
]